If 4 1/a x b 2/3=7, find the values of a and b.

Question

If \(4\cfrac 1a\times b\cfrac23=7\), find the values of a and b.

(a) 1, 5

(b) 2, 3

(c) 3, 2

(d) 5, 1

Answer 1

Correct option : (d) 5 , 1

\(4\cfrac 1a\times b\cfrac23=7\)

(A) If \(a = 1, b = 5\) then \(4\cfrac11 \times 5\cfrac23=4\times \cfrac{17}{3}=\cfrac{68}{3}\ne 7\)

(B) If \(a = 2, b = 3\) then \(4\cfrac12 \times 3\cfrac23=\cfrac92\times \cfrac{11}{3}=\cfrac{33}{2}\ne 7\)

(C) If \(a = 3, b = 2\) then \(4\cfrac13 \times 2\cfrac23=\cfrac{13}{3}\times \cfrac{8}{3}=\cfrac{104}{9}\ne 7\)

(D) If \(a = 5, b = 1\) then \(4\cfrac15 \times 1\cfrac23=\cfrac{21}{5}\times \cfrac{5}{3}=\cfrac{21}{3}= 7\)

Hence, a = 5, b = 1.