A number is increased by 20% and then decreased by 20%. What is the net change in the number?
4% decrease
Take the number as 100 for easy calculation. After a 20% increase it becomes \(100 \times 1.20 = 120\).
The 20% decrease now applies to 120, not to the original 100: \(120 \times 0.80 = 96\).
The final value 96 is less than the original 100, a fall of 4 in 100, i.e. a 4% decrease. (Equivalently, the net factor is \(1.2 \times 0.8 = 0.96\).)
Hence, there is a net 4% decrease.
Similar Questions
- A student's marks in Mathematics were 20% more than in Physics. If he scored 72 in Physics, how many marks did he score in Mathematics?
- An employee contributes 20% of their salary to charity. From the remaining amount, 40% is allocated to investments. The rest is divided for education and travel in the ratio 7: 5. If the expense on travel is ₹6000, what is the employee's total salary?
- A number was mistakenly increased by 25% instead of decreased by 20%. By what percent is the final result more than the CORRECT value?
- A person spends 80% of his income and saves ₹2000. What is his income?
- The population of a village increases by 8% annually. If the current population is 58,320, what was it two years ago (approx)?
- A man spends 80% of his income. His income has increased by 25%, but his expenditure remains the same. By what percent have his savings increased?
- Out of her total monthly income, a woman spends 60% on household expenses and 15% on savings. The remaining is spent on other items. What percentage of her income is spent on these other items?
- A's salary is 40% more than B's. If B's salary increases by 20% and A's increases by x%, then A's new salary becomes 25% more than B's new salary. What is the value of x?
- The value of a machine depreciates 10% in the first year, 20% in the second year, and 30% in the third year. If the initial value was Rs. 10,000, what is its value at the end of 3 years?
- The difference between 20% of a number and 10% of the same number is 120. What is the number?
Important Questions from Percentage
Radha saves 25% of her income. If her expenditure increases by 20% and her income increases by 29%, then her savings increase by;
The income of A is 45% more than the income of B and the income of C is 60% less than the sum of the incomes of A and B. The income of D is 20% more than that of C. If the difference between the incomes of B and D is Rs. 13200, then the income (in Rs.) of C is:
The price of cooking oil increased by 25%. Find by how much percentage a family must reduce its consumption in order to maintain the same budget.
The population of a city increased by 30% in the first year and decreased by 15% in the next year. If the present population is 11,050 then population 2 years ago was:
The income of A is 30% less than the income of B and the income of B is 137.5% more than that of C. If the income of A is Rs. 28500 less than that of B, then the income (in Rs.) of C is:
