Question

The average age of a group of persons going for picnic is 16 years. Twenty new persons with an average age of 15 years join the group on the spot due to which their average age becomes 15.5 years. The number of persons initially going for picnic is :​

Answer 1

Step-by-step explanation:

sum of people initially going to picnic = x

no.of people going = y

we have to find y

given x / y=16 => x = 16y

other sum of 20 new / 20 = 15

sum of 20 new = 15×20 =300

new avg= (x+sum of 20 new )/y+20= 15.5

= (16y+300)/y+20=15.5

= 16y + 300= 15.5y+310

= 1.5y=10

=> y~6