Percentage Practice Test 3 with solutions

Question : 14 of 40

Marks: +1, -0

The cost of a pen is thrice than that of an eraser and the cost of an eraser is 20% less than that of a pencil. If the cost of each time is decreased by 25%, then the percentage decrease in the cost of 5 pens, 10 erasers and 20 pencils is:

Validate

Solution:

Let the cost of a pencil be Rs x.
The cost of an eraser = 80% of x

=80/100x=\Rs.4/5x

Cost of a pen

\Rs.(3×4/5x)=\Rs. 12/5x

Now the total cost of 5 pens, 10 erasers and 20 pencils is

=5(12/5x)+10(80/100x)+20x

= 12x + 8x + 20x

= 40x

Increased cost

=40x×75/100=40x×3/4=30x

∴ Required percentage

={30x}/{40x}×100x=75%

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