SETS 2

In Bibanja district the number of people who speak Kiswahili or Lingala is 390. 200 of them speak Kiswahili and 300 of them speak Lingala. How many speak both languages?

solution

In most cases, OR stands for union whereas AND/BOTH, stands for intersection.

Let Kiswahili=n(K), Lingala= n(L).

n(K)= 200 ,

n(L)= 300,

n(KuL) = 390,

n(KnL)=?

n(KuL) = n(K) + n(L) - n(KnL)

390  =  200 + 300 – n(KnL)

390  =  500 – n(KnL)

n(KnL) =  500 – 390

n(EnF) =  110

Hence n(EnF) = 110 answer

TRY THIS……………………………….. 

In Nyakabanga district the number of people who speak Kiswahili or Spanish is 390. 250 of them speak Kiswahili and 350 of them speak Spanish. How many speak both languages?