# DBT JRF 2020 — Question 4

Exam: DBT JRF 2020 · Section: A · Topic: Aptitude & Reasoning · Difficulty: Medium

## Question

In the first semester course work at the Biotech Institute, 50 students signed up for both Genetics and Statistics, and 90 students signed up for either Genetics or Statistics. If 25 students are taking Genetics but are not taking Statistics, how many students are taking Statistics but not taking Genetics?

## Options

- **A.** 25
- **B.** 15
- **C.** 65
- **D.** 35

## Answer

Option B

## Explanation

Using the inclusion-exclusion principle: |G ∪ S| = |G| + |S| - |G ∩ S|. Total (either) = 90, Both (G ∩ S) = 50. Therefore |G| + |S| = 90 + 50 = 140. Only Genetics (G only) = 25, so |G| = 25 + 50 = 75. Therefore |S| = 140 - 75 = 65. Only Statistics = 65 - 50 = 15. Students taking Statistics but NOT Genetics = 15.

Source: https://mypyqbuddy.com/questions/in-the-first-semester-course-work-at-the-6a05a8a02adafec4702931ea