Solution: suppose the speed of the spacecraft is x km/s.
40/57x=8
40/57x÷40/57=8÷40/57
x=57/5
Solution 2
8÷40/57=57/5 (km/s)
4.
Solution: let this bucket weigh x kilograms.
x- 1/ 10x=9
( 1- 1/ 10)x=9
x=9÷9/ 10
x= 10
or
9÷ (1-110) =10 (kg)
5.
15/ 16÷3= 15/ 16× 1/5=3/ 16
12/25÷8= 12/25× 1/8=3/50
8÷4/5=8×4/5= 10
2 1/40÷7/8=2 1/40×8/7=3/5
16÷2/ 17= 16× 17/2= 136
7/24÷6/49=7/24× 17/2=343/ 144
18/35÷0.6×2/3
4/9× 15/ 16÷5/6
=35/ 18
× 10/6×2/3
=5/ 12×6/5
=6/7×
2/3
= 1/2
= 12/2 1=4/7
(
2-0.6)÷7/ 15
35/64÷( 1/8+3/4)
= 1.4× 15/7
=35/64÷7/8
=3
=35/64×8/7
=5/8