When a b c de f g h ij k l is expanded how many ter

When (a + b + c + d)(e + f + g + h + i)(j + k + l) is expanded, how many terms will there be? How many factors are there in each term?

Solution

In the first factor there are 4 terms a, b, c, d in second factor there are five terms e, f, g, h, i So when we multiple these two there will be 4*5=20 terms each term having two factors like ab, de, di,

When these twenty terms are multiplied to third factor having three terms j, k, l

We obtain 60 terms like aej, bgk, chl,....

There are three factors in each term