Question

A number is first increased by 40% and then decreased by 25%, again increased by 15% and then decreased by 20%, find the percentage of total increase or decrease in the number?

● (a) 7.2% decrease
● (b) 3.4% increase
● (c) 6.4% increase
● (d) 3.4% decrease

ANSWER IMMEDIATELY ​

Answer 1

Answer:

Let the number be x

Let the number be x⇒

Let the number be x⇒ ⇒

Let the number be x⇒ ⇒ ⇒ 0.966x

Let the number be x⇒ ⇒ ⇒ 0.966x⇒ 0.966x is less than x

Let the number be x⇒ ⇒ ⇒ 0.966x⇒ 0.966x is less than x ⇒ Decrease per cent in the number =

Let the number be x⇒ ⇒ ⇒ 0.966x⇒ 0.966x is less than x ⇒ Decrease per cent in the number = ∴ Net decrease per cent in the number is 3.4%

Answer 2

Answer:

(b).

Step-by-step explanation:

Let the number be 100

increase by 40% gives 140

Decrease by 25% gives 140 * 0.75 = 105

increase by 15% = 105 * 1.15 = 120.75

Decrease by 20 % = 120.75 * 0.80 = 96.6

So its a decrease of 100 - 96.6 = 3.4%