Ask a few elementary school questions, be detailed, and you can use a variety of methods

1.A and B work together on a batch of parts. It is scheduled to be completed in 6 hours. Now first by having done hours later. A then joins the cooperation. It took 3/5 of an hour to complete the task more than planned. A is known to do 54 per hour. Q: How many parts are there?

Solution: According to the title, the actual time is 6+3 5 hours, and the two have cooperated for hours, which is less than the planned cooperation time, and the workload of the hourly cooperation is the workload of A alone hour.

Let B alone make x parts per hour.

54+x）×

Solve x 36

The total number of parts is (54+36) 6 540.

2 two items. $240 per piece. One of them earns 20 percent and one loses 20 percentQ: Did you make a profit or lose money after selling?

Solution: Find the original price of each item separately.

One is 240 (1+20) 200 yuan.

The other is $240 (1-20) $300.

The original price is a total of 200 + 300 500 yuan.

Lost 500-240-240 20 yuan.

5 B + A + B) = 6 (A + B).

B = A, B = B = 81, 81 + 54 = 135

240 (1+20) 200 yuan.

The other is $240 (1-20) $300.

A total of 200+300 500 yuan.

Lost 500-240-240 20 yuan.

The first question above is wrong, the workload of hourly cooperation is the workload of B's individual hour, not A's.

Because the first hour is done by B, and the second hour is cooperative, that is:

B + A + B) = 6 (A + B).

B = A. B = B = 81 81 + 54 = 135

The ratio of the area of the circle to the area of the first square is:

The ratio to the area of the second square is: 4*2::

The ratio to the area of the third square is: 8*2::

The ratio of the area of the circle to the area of the sixth square is: 16*2*2*2::

Note: (: stands for "than" * for "multiplication".

(1) r: s = 4 (r: circle area s: square area) (2) r: s = 8

3) r ：s =π4*(2*2)) 16(4) r ：s = 4*(2*2*2*2*2)) 128

Five-sixths of two-thirds is (five-ninth) and two-thirds (five-fourths) is five-sixths.

Eight-tenths multiplied by seven-ninths equals eight-sevenths of twenty-sevenths is changed to two divisions, and the equation is (denominator divides numerator).

A tunnel 4/5 of a kilometer long is repaired every day. Repair (4/30) kilometers every day, and (5) days can be completed.

Answer: Yuan Shen stool hail travel case filial piety.

<> picture of the antling stove is stuffy with ants.

<> his own Hui Chain looked at the former sail grandson and returned to the sedan chair.

Freight car speed = 60 (1 + 1 11) = 55, travel time = 35 (60-55) = 7, railway length = (55 + 60) * 7 = 805km

Wrong. The circumference of the base surface is enlarged by 2 times, that is, the radius of the base circle is expanded by 2 times.

Since the height is constant, the surface area = the base circumference multiplied by the height, the height is constant, and the surface area is the same.

Volume = base area multiplied by height, the base area is expanded by 2 times, so the volume is expanded by 2 times.

No, the volume is also 4 times larger.