Question

A number is increased by 25% and then it is decrease by 15% calculate the net increase or decrease in the value of the number.

Answer 1

Gɪᴠᴇɴ :-

• A number is increased by 25% .
• Then it is decrease by 15% .

Tᴏ Fɪɴᴅ :-

• The Net Increase or Decrease in the value of the number. ?

Sᴏʟᴜᴛɪᴏɴ :-

Let us Assume That, The original Number is 100x.

Case 1 :- Number is increased by 25% .

So,

→ Increased Number = Original Number + (25% of Original Number)

→ Increased Number = Original Number + (100 + 25%)

→ Increased Number = Original Number * (125/100)

→ Increased Number = 100x * (125/100)

→ Increased Number = 125x.

_______________

Case 2 :- Increased Number is Decreased by 15% Now.

So,

→ Decreased Number = Increased Number - 15% of Increased Number

→ Decreased Number = 85% of Increased Number

→ Decreased Number = Increased Number * (85/100)

→ Decreased Number = (125x * 85) / 100

→ Decreased Number = 106.25x .

_______________

Therefore,

→ Net Increase in The Original Number = 106.25x - 100x = 6.25x.

→ % increase = (6.25x * 100) / 100x = 6.25% (Ans.)

Hence , Net increase in The Original Number Is 6.25% .

Answer 2

Answer:

let the number be x,

after 25% increase

new number = x + 25x/100 = 125x/100 = 5x/4

after 15 % decrease

new number = 5x/4 - 5x × 15/4×100

= 5x/4 - 3x/16

= 17x/16

net increase = 17x/16 - x = x/16

percentage increase = x/16x × 100 = 1/16 × 100 = 100/16% = 25/4% = 6.25%