Question

(4.2+3又1/5)÷[(21.74-21)×2/3]

Answer 1

(4.2+3又1/5)÷[(21.74-21)×2/3]

=(4.2+3.2)÷[0.74×2/3]

=7.4×3/(0.74×2)

=15

1.甲数的2/3是18,它的25％比乙数少25,

乙数是=18/(2/3) *25% +25=127/4

2.用16个3/4的和去除45的10％与1/2的差,

商是=(45*10% -1/2)/(16*3/4)=1/3

3.甲数是50 的1/5,乙数的5/8是25,

甲数是乙数的=（50*1/5）/[25/（5/8）]*100%=25%