Answer:

Step-by-step explanation:
Let
y --->Mala's age
x---> sister's age
we know that
---> equation A
so
The sum of ages of the sisters is

substitute equation A in the expression of the sum of ages

simplify

Answer:
7
Step-by-step explanation:
16x-80+18=4x+22
16x-62=4x+22
12x-62=22
12x=84
x=7
3 by 2 by 4
volume =24 (units)
4 by 5 by 5
volume= 100(units)