Respuesta :
Answer: 12%
Step-by-step explanation:
Let the original salary be Rs a
Salary after increase = a + 40% of a
= a + 40a/100
= 140a/100
= 14a/10
= 7a/ 5
Salary after Decrease = 7a/5 - 20% of 7a/5
= 7a/5 - 20× 7a / 100 × 5
= 7a/5 - 7a/25
= ( 35a - 7a) / 25
= 28a/25
Absolute increase = 28a/25 - a
= 3a/25
Percentage = 3a/25 ×100 / a
= 3 × 4
= 12%
Given question is incomplete; here is the complete question.
How did the temperature change if: at first it increased by 25 % and then decreased by 40% ?
Temperature will finally decrease by 25%.
Let the initial temperature is x° C,
If the temperature is increased by 25%,
Then the final temperature = x° + 25% of x°
= [tex]x+\frac{25x}{100}[/tex]
= [tex]x+0.25x[/tex]
= [tex]1.25x^\circ[/tex]
Followed by the decrease in temperature by 40%,
Then final temperature = 1.25x° - 40% of (1.25x°)
= 1.25x° - 0.5x°
= 0.75x°
Therefore, percentage decrease in temperature from initial temperature x°,
Percentage decrease = [tex]\frac{x^\circ-0.75x^\circ}{x^\circ}\times 100[/tex]
= 25%
Temperature will finally decrease by 25% when increased initially by 25% then decreased by 40%.
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