shoes + shoes + shoes = 30
shoes + (boy + whistle) + (boy + whistle) = 20
(Boy + whistle) + 2(whistles) + 2(whistles) = 13
shoes + (boy) x (whistle) = ?
First equation:
shoes + shoes + shoes = 30
3(shoes) = 30
shoes = 10
Second equation for the (boy + whistle) value:
shoes + (boy+ whistle) + (boy+ whistle) = 20
10 + 2(boy+ whistle) = 20
2(boy + whistle) = 10
Boy + whistle = 5
Third equation for the whistle:
(Boy+ whistle) + 2(whistles) + 2(whistles) = 13
5 + 4(whistles) = 13
4(whistles) = 8
whistle = 2
Then put the value of whistle to find boy
Boy + whistle = 5
Boy+ 2 = 5
Boy = 3
Finding the answer-
shoes + [(boy) x (whistle)] = ?
10 +( 3 x 2)
= 10 + (3 x 2)
= 10 + 6
= 16
Answer is 16