1、 1.5*(4/5)/( 18/5)= 1/3

2、[ 10*(2/5)- 1.75]/75%=(9/4)/(3/4)=3

Let this number be x.

8.7-X*(4/7)=7.3

X=49/20

4、[( 1056/32)+67]*50= 1650

solve problems

1、400/700=57. 1%

The planned enrollment is 57.65438+ 0% of the enrollment.

2.240+(240 *10)/15 = 400km.

A and b are 400 kilometers apart.

3.6/[12 * (3/4)-7] *12 = 21.6 ton

The first coal pile was originally 2 1.6 tons.

4. Scheme 1 (proportional method): Assume that this pile of coal can actually burn for x days (the more coal burned every day, the fewer days it can burn, so the relationship between them is inversely proportional).

750/600=X/24

X=30 days

Option 2: (750*24)/600=30 days.

This pile of coal can actually burn for 30 days.