In the expansion of

MATHEMATICS · Single correct · A Level · Mathematics · Sequences and series · Sequences and series

Problem

In the expansion of

(a+bx)^{6}

, the coefficient of

x^{3}

is 40 while that of

x^{4}

is 50. Find the ratio

a:b

. (a)

5:3

(b)

4:5

(c)

3:5

(d)

2:3