Math problems, help. To calculate, to answer.

1: Set to sell x boxes of apples in April.

2x-20=240

Solution x=130

2: Set: a brush x yuan, a pen y yuan.

2x+3y=80

2x+5y=104

Solution: x=22

y=12

Sold in April x = 130 cases of apples.

2x+5y=104 brush x=22 fountain pen y=12

1) Set x boxes to be sold in April.

2x-20=240

2x=260

x=130A:

2) Set a brush for X yuan and a pen for a Y yuan.

2x+3y=80

2x+5y=104

The solution is x=22 y=12A:

240x2+20=500

Fountain pen = (104-80) divided by 2 and then counted as a brush.

1. May is 240, and from the title, it can be seen that the double of April is 240 + 20 = 260, so April is 260 2 = 130

2, bought 2 brushes and four pens with 80 yuan, the same bought 2 brushes and 5 pens with 104 yuan, that is to say, bought 2 pens with 104-80 = 24 yuan, the unit price of the pen is 24 2 = 12 yuan, so the brush is (80-12 * 3) 2 = 22 yuan.

1. (240+20) 2=130 (box).

80 = 24 (yuan).

Steel: 24 2 = 12 (yuan).

Mao: 12 * 3 = 36 (yuan).

80-36 = 44 (yuan).

44 2=22 (yuan).

1. Set the sale of apples x box in April 2x+20=240 x=110

2. Set the unit price of the brush to be x yuan and the fountain pen ** to be y yuan 2x+3y=80 2x+5y=104 to get x=28 y=8

(1) 200 (1-20%) = 250 (yuan) ......Original price (2) (250 + 80) * (1-20%) = 264 (yuan) ......Method 1: 250 + 80-100 = 230 (yuan) ......The second way is 264 230, so the second way is cost-effective.

1）250*（100%-20%）=200

2) All are purchased at a 25% discount, and a total of money is spent: 250*(100%-25%)=

According to the purchase of 200 yuan to send a shopping coupon: since the shoes only need 98 yuan, you can directly use the shopping coupon, so a total of 250 yuan can be spent.

Because 261>250

Therefore, the two ways are finally compared: shopping according to method 2 is more cost-effective, and you can save 11 yuan, and the "*" in the above formula is the meaning of multiplication.

(1) 200 (1-20%) = 250 (yuan) ......

2) The second option is more cost-effective. Because the clothes are 250 yuan, and the 200 yuan is full, you can get a 100 yuan shopping coupon, and the shoes can be used without spending money, and you can use the shopping coupon to offset it, only 250 yuan in total. If it is the first method, 80 * 80% = 64 yuan, plus 200 yuan of clothes is not cost-effective, it needs 264 yuan.

(1) 200/(1-20%)=250

2) Method 1: (250+80) 80%=264Method 2: 250+80-100=230

So the second way is cost-effective.

The length of the bottom is 2+5=7

The height is 10*2 5=4

The area is (2+7)*4 2=18

Its area is 18 square centimeters.

1. Start making 24 per day, 1 4 7 = 1 28 per day, a total of 24 1 28 = 672.

After the improvement, 3 4 12 = 1 16 per day, and the number of pieces is 672 * 1 16 = 42.

2. If the car travels 1 4 = 1 4 per hour, then the truck travels per hour = 1 4 * (1-20%) = 1 5, then the truck takes 5 hours.

3. Xiaoqing loads 1 1 5 = 5 baskets per hour, Xiao Ming loads 1 1 6 = 6 baskets per hour, then two people load a total of 11 baskets per hour, then two people load 3 baskets A total of time = 3 11 hours.

4. This batch of coal is 45 (30%-25%) = 900 tons, and the amount of B transportation = 45% * 900 = 405 tons.

5. Set rice x kg, then flour 5x kg, x 30 = (5x-225) 75, x rice = 90 kg, 5x flour = 450

6. Let there be x large barrels and (50-x) small barrels, 4x+2*(50-x)=120, x large barrels = 10, and 50-x small barrels = 40

1.Find the total number of parts first.

24*7) (1 4) = 672 (pcs).

After 7 days, 672-24*7=504 (days) remains, and finally 504 12=42 (days).

2.4 80% = 5 (hours).

3.The set time is t hours.

t/(1/5)+t/(1/6)=3

The solution is t=3 11 (hours).

4.Set up car B to transport x tons.

x 45%)*30%-(x 45%)*25%=45 to get x=405 (tons).

5.Set rice x kilograms, flour 5 x kilograms.

x/30=(5x-225)/75

The solution yields x=90 (kilograms).

5x = 450 (kg).

6.Let there be x large barrels and (50-x) small barrels.

4x+2*(50-x)=120

The solution yields x=10 (pcs).

50-x=40 (pcs).

1. Solution: The number of parts made in 7 days: 7 * 24 = 168 The whole batch of parts is total: 168 * 4 = 672

Remaining parts: 672-168=504

Later an average of parts were made per day: 504 12 = 42

You're in sixth grade, I've done that.

168 1/4 = 672 (pcs).

672-168) 12=42 (pcs).

I hope you will ask questions after thinking about it、、、 if you think about it seriously, I suggest you read the book carefully, ask the teachers and classmates, and ask the teachers

How many percent widened the circumstance, so divide the widened by the original (25-10) 10 So the extension letter is widened by 150%.

Ice is 10 percent less than water 9 kg of ice and 10 kg of water.

80 percent 120 percent of the wheel

Note that whoever you compare with will be the denominator, and there will be no disadvantage from now on.

Question 1 (5 8 + 1 4) 7 16 = 2

A: This number is 2

Question 2 (45 10%)

Dolphins: 160: = 64

Sailfish: 58: = 116

Sailfish swim the fastest.

Dolphins can swim 160km per hour, that is, they can swim 32km per hour.