Question

the ratio of zinc and copper in an alloy is 7.9, if the weight of the copper in the alloy is 11.7kg. find the weight of the zinc in the alloy

Answer 1

7x:9x
9x=11.7,x=11.7/9=1.3
7x=7×1.3=9.1

Answer 2

Ratio of zinc and copper = 7:9
which is 7x:9x
Copper= 9x= 11.7 kg
x=
$\frac{11.7}{9}$
= 1.3
Zinc = 7x = 7 × 1.3 = 9.1 kg