P's income is 250 percent of Q's income and P's expenditure is 180 percent of Q's expenditure. If P's income is 400 percent of Q's expenditure, then what is the respective ratio of P's savings and Q's savings ?

11 : 3

Let Q's income be x,

P's income = 250% of x 

                = $\frac{250}{100}$ x

                 = $\frac{5}{2}$ x

Similarly, if we assume that Q's expenditure is y,

P's expenditure = 180% of y

                       = $\frac{180}{100}$ y

                       = $\frac{9}{5}$ y

According to the question, 

P's income is 400 percent of Q's expenditure

⇒ $\frac{5}{2}$ x = 400% of x

⇒     x   = $\frac{8}{5}$ y 

P's savings = $\frac{5}{2}$ x - $\frac{9}{5}$ y 

         (using the relation between x and y) 

                 = [$\frac{5 \times 8}{2 \times 5}$ - $\frac{9}{5}$] y 

                 =  $\frac{11}{5}$ y 

Q's savings = x - y

          (using the relation between x and y)

                 = $\frac{8}{5}$ y - y

                  = $\frac{3}{5}$ y 

⇒ Ratio of P and Q's savings = $\frac{11}{5}$ y  : $\frac{3}{5}$ y 

                                          = 11 : 3