the mean of the distribution is 145.find p and q

Question

class :        100-120  120-140  140-160   160-180   180-200

frequency :10             p              10             q              5       =  60

Answer 1

By the problem

10+p+10+q+5=60

=>q =35-p

Class .              Mid value.    Freq

100-120.            110                 10

120-140             130                   p

140-160 .            150.                 10

160- 180 .           170.           35 -p

180-200 .             190.               5

Given mean = 145

110*10+130*p+150*10+170*(35-p)+190*5=145*60

=>50p= 1100+1500+5950+950-8700

=>50p=800

=>p =16