John bought two types of bulbs A and B at Ksh 60 and Ksh 56 respectly. He bought a total of 50 bulbs of types at a total of Ksh 2872. determine the number of Type A bulbs that he bought.

Answer 1

add up the bulbs and the costs:
A+B = 50
60A+56B = 2872
so now find A.

Answer 2

B = 50 - A

60A + 56(50 - A) = 2872
60A + 2800 - 56A = 2872
4A = 72
A = 18