If a + 2b = 6 and ab = 4, what is \(\frac{2}{a} + \frac{1}{b}\) ?

A \(\frac{1}{2}\)

B 1

C \(\frac{3}{2}\)

D 2

Correct Answer: Option C

Solution:

যদি a + 2b = 6 এবং ab = 4 হয় তাহলে \(\frac{2}{a} + \frac{1}{b}\) এর মান কত ?

দেওয়া আছে, a + 2b = 6 ......... (1)

এবং ab = 4 ..............(2)

এখন, সমীকরণ (1) কে \(\frac{1}{{ab}}\) দিয়ে গুণ করি

\(\frac{1}{{ab}} \times a + \frac{1}{{ab}} \times 2b = 6 \times \frac{1}{{ab}}\)

=> \(\frac{1}{b} + \frac{2}{a} = \frac{6}{{ab}}\) => \(\frac{2}{a} + \frac{1}{b} = \frac{6}{4}\) \(\frac{2}{a} + \frac{1}{b} = \frac{3}{2}\)