Question

the total weight of the mixture of two things a and b is 50 kg if A and B are mixed in the ratio 3:7 find the quantity,B in the mixture

Answer 1

let mixture are in ratio be 3x and 7x
3x + 7x = 50
10x = 50
x = 5
b = 35 kg

Answer 2

first step

Sum of the ratio 3:7- 3+7=10

second step

What is the total weight-50kg

third step

Quantity of A in the mixture- $\frac{3}{10} * 50$=15

fourth step

Quantity of B in a mixture-$\frac{7}{10} * 50$=35

So, the quantity of B in a mixture is 35kg.

(note, i have find the quantity of A just for better understanding, that step is optional)