Junu's expenditure and savings are in the ratio 4:1.His income increases by 20% .If his savings increases by 12% by how much percentage would his expenditure increase?
I was struck here How to proceed?
${Expenditure = {4\over 5} \text{ } Savings = {1\over 5} }$
${20\text{%} \text{ increase of 5 is 1+5=6 }}$
If his income is $1$ his expenditure is $0.8$ and savings is $0.2$.
His income increases to $1.2$ and savings to $0.2(1+0.12)=0.224$.
His new expenditures are $1.2-0.224=0.976$.
The percentage expenditure in expenses is $\frac {0.976}{0.8}-1=0.22=22\%$