Question : 4 boys and 3 girls spent Rs. 120 on an average, of which boys spent Rs. 150 on an average. Then the average amount spent by the girls is:
Option 1: Rs. 80
Option 2: Rs. 60
Option 3: Rs. 90
Option 4: Rs. 100
Correct Answer: Rs. 80
Solution :
The average expense of 4 boys and 3 girls is Rs. 120.
Total expense = 120 × 7 = Rs. 840
The average expense of 4 boys is Rs. 150
Total expense of 4 boys = 150 × 4 = Rs. 600
Total expense of 3 girls = total expense – total expense of 4 boys = 840 – 600 = Rs. 240
So, the average amount spent by the girls =
Hence, the correct answer is Rs. 80.