Shortcut Trick
Total population = 385,000, Males = 168,000 ⇒ Females = 217,000
Ratio of Male to Female = 168,000 : 217,000 = 24 : 31
Using the Alligation method on literacy rates:
(Female % − 52%) ÷ (52% − 21%) = Male Ratio ÷ Female Ratio = 24 ÷ 31
⇒ (Female % − 52%) ÷ 31% = 24 ÷ 31 ⇒ Female % − 52% = 24% ⇒ Female % = 76%
∴ The correct answer is 76%.
Alternate Method
Given:
Total population = 385,000
Total males = 168,000
Overall literate population = 52%
Male literate population = 21%
Total Pop = 385,000
Total Literate = 200,200
Male = 168,000
Literate = 35,280
Female = 217,000
Literate = 164,920
Female % = (164,920 ÷ 217,000) × 100 = 76%
Calculations:
⇒ Total females = Total population − Total males
⇒ Total females = 385,000 − 168,000 = 217,000
⇒ Total literate population = 52% of 385,000 = (52 ÷ 100) × 385,000 = 200,200
⇒ Total literate males = 21% of 168,000 = (21 ÷ 100) × 168,000 = 35,280
⇒ Total literate females = Total literate population − Total literate males
⇒ Total literate females = 200,200 − 35,280 = 164,920
⇒ Percentage of literate females = (Total literate females ÷ Total females) × 100
⇒ Percentage of literate females = (164,920 ÷ 217,000) × 100
⇒ Percentage of literate females = 164,920 ÷ 2,170 = 16,492 ÷ 217 = 76%
∴ The correct answer is 76%.
Additional Information
Alligation Method
It is a quick trick used to find the ratio in which two quantities are mixed or to find an unknown percentage. Here, it helps bypass large percentage calculations by operating purely on the sub-group ratios.
Weighted Average
The overall percentage of a combined group is the weighted average of the individual percentages: (n1x1 + n2x2) ÷ (n1 + n2). By simplifying n1 and n2 to their lowest ratio form, calculation steps are vastly minimized.
Simplifying Ratios
When working with percentages, large absolute values (like 168,000 and 217,000) can be simplified to their simplest ratio (24:31). This makes calculations considerably faster without altering the final percentage outcome.