In a class average age of 15 boys is 11. If 5 boys each of age 9 years are added, what would be the new average?
Answer & explanation
Correct answer: option 1
Total age of boys in a class = 15 x 11 = 165
Total age after adding 5 new boys = 165 + 9 x 5 = 210
New average = \(\frac{210 }{ \text{15 + 5}}\)
New average = \(\frac{210 }{ 20}\)
New average = 10.5