GIVEN: In the year 2018, the ratio of number of males and number of females in a village was 5 : 3. In 2019, number of male increases by 10% while number of female decreases by 10%. FORMULA USED: X% of a number Y = (Y × X)/100 If a number ‘Y’ is increased by X%, increased number = Y × (1 + X/100) CALCULATION: Let number of males and females in village in 2018 ware ‘5x’ and ‘3x’ respectively. So, Number of males in 2019 = 110% of 5x = 5.5x Number of females in 2019 = 90% of 3x = 2.7x So, Total population in 2019 = 5.5x + 2.7x = 8.2x ∴ Required percentage increment = [(8.2x – 8x)/8x] × 100 = 2.5%