SETS 1

In Bibanja district the number of people who speak Kiswahili or Lingala is 400. 250 of them speak Kiswahili and 350 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)= 250 ,

n(L)= 350,

n(KuL) = 400,

n(KnL)=?

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

400  =  250 + 350 – n(KnL)

400  =  600 – n(KnL)

n(KnL) =  600 – 400 [– n(KnL) goes to the left it will be +ve

n(EnF) =  200

Hence n(EnF)=200 answer

TRY THIS...................

In Bibanja district the number of people who speak English or Lingala is 500. 270 of them speak English and 380 of them speak Lingala. How many speak both languages?