Question

甲数比乙数的5倍少15,甲数比丙数的5倍多12,已知丙数比乙数的2/3少1.1,求甲数是多少?

Answer 1

设甲为X 乙为Y 丙为Z

x+15=5y x-12=5z y=X/5+3 z=x/5-2.4

x/5-2.4+1.1=(x/5+3)*2/3

x/5-1.3=2X/15+2

X/5-2X/15=3.3

X/15=3.3

X=49.5

甲数是49.5 乙是12.9 丙为7.5