Richard receives an increment in his salary. His salary pres

Dear jaswant16041952,

The explanation is simple : Lets say the family income previously was X and Richards salary constituted to 0.2X. After the increment, Richards salary is 0.3X. In order to calculate by how percentage points did Richard's salary increase as a percentage of his family's total salary : (0.3X-0.2X)/X= 10%.

Hope it helps.

Papua

The salary of Richard as a percentage of his family's total income was 20%
The salary of Richard as a percentage of his family's total income now is 30%
The percentage points that have increased is 10 (from 20% to 30%).
Answer (C)

Now the question stem can be changed a little to change the entire solution. Let's look at two variations:

Variation 1: By what percent did the salary of Richard as a percentage of his family's total income increase?

Salary of Richard as a percentage of his family's total income was = 20%
Salary of Richard as a percentage of his family's total income now = 30%
The increase is from 20 to 30. This is an increase of 50% ( = (30 - 20)/20 * 100)

Variation 2: By what percent did the salary of Richard increase?
Say Richard's salary was = 20 and his family's total income was = 100
His salary increased by x and his family's total income also increased by x
(20+x)/(100+x) = 30/100
x = 100/7 = 14(2/7)
New salary of Richard = 20 + 14(2/7)
% increase in his salary = 14(2/7)/20 * 100 = 71.4%

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