if p is the greatest prime factor of 38 and f is the greatest prime factor of 100, then p+f=

Factors of 38:

2*19

Factors of 100:

2*2*5*5

So the greatest for 38 is 19 and for 100 it's 5

Fill in p+f giving you 19+5

Add them and you get 24

Greatest prime factor of 38 = 19

Greatest prime factor of 100 = 5

So....p + f  = 24