The income of A is 50% more than that of B. If the income of A is increased by 40% and the income of B is increased by 90%, then the percentage increase in their combined income will be:

As per the condition given in the question,

Let the income of B is = x

So, the income of A $$\dfrac{150\times x}{100}=1.5x$$

A's income increased by 40%, so new income $$=\dfrac{140\times(1.5x)}{100}=2.1x$$

B's income increased by 90%, so new income $$=\dfrac{190 x}{100}=1.9x$$

So, combined income after increase $$=1.9x+2.1x =4x$$

And combined income before increase $$=x+1.5x=2.5x$$

Hence, percentage of increased salary $$\dfrac{(4x-2.5x)\times 100}{2.5x}=\dfrac{1.5x \times 100}{2.5x}=60\%$$