The ratio of the expenditure of P, Q and R is 207 : 195 : 217 respectively and their savings are 10%, 25% and 30% of their income.  If the sum of their income is Rs 8000.  Find the difference between the income of Q and R.

500

Let income of P, Q, and R = P, Q and R

ATQ,

⇒ 90% P : 75% Q : 70% R = 207 : 195 : 217

⇒ 18P : 15Q : 14R = 207 : 195 : 217

Here,

18P = 207 ⇒ P = 11.5R

15Q = 195 ⇒ Q = 13R

14R = 217 ⇒  R = 15.5R

Ratio is: 

  P     :    Q     :     R

11.5   :    13    :   15.5  or

  23    :    26    :     31

Total income = (23 + 26 + 31)R = 8000

⇒ 80R = 8000

⇒ 1R = 100

Difference between the income of Q and R = (31 - 26 )R = 5R = 5 × 100 = 500