Question

Electric Supply Company raises its charges by 20% and later increases the new charges by 20% if the total had been made all at once ,to what percentage would it have been equivalent
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Answer 1

Let the CP be x,

So, SP after first raise in charges,

= x + 20% of x

= x + 20x / 100

= 120x / 100

SP after second raise in charge,

= 120x / 100 + 20% of 120x / 100

= 120x / 100 + 20/100 * 120x / 100

= 120x / 100 + 12x/50

= 144x / 100

Therefore, total raise in charges

= (Profit/CP * 100) %

= {(44x/100) / x * 100} %

= 44 %

So, the company will have to raise its charges by 44% at once.