Explanation:
the numbers of the yellow and white counters
= 288- 38 = 250.
the ratio of yellow to white = 1:4
so,
the numbers of the yellow counters =
1/(1+4) × 250 =1/5 ×250 = 50
the numbers of the white counters =
4/(1+4) ×250 = 4/5 ×250 = 200
and the numbers of the red counters = 38