Ali has x apples. Whether he divides the apples among 4 boys, 5 boys or 9 boys, the remainder is 3,4 and 8 respectively.
what is the smallest possible value of x?
In each case, if Ali had one more apple then he could share them all out equally. So, your answer is one less than the lowest common multiple of 4, 5 and 9. 4, 5 and 9 share no common factors, so their lowest common multiple is simply their product. 4x5x9 = 180, so the minimum number of apples Ali can have is 179.
Check: 179/4 = 44 r 3
179/5 = 35 r 4
179/9 = 19 r 8
Why did the vector cross the road?
It wanted to be normal.