Question

50 students were asked what they did last night. 16 said they read a book, 41 said they watched TV, 7 said they did neither, how many students did both​

Answer 1

Answer:

14 students

Step-by-step explanation:

Given

Let:

$b \to$ read a book

$t \to$ watched TV

So, we have:

$n = 50$ -- total

$b = 16$

$t = 41$

$none = 7$

Required

Students that did both (x)

This is calculated using:

$Total = Books\ only + TV\ only + Both + None$

So, we have:

$n = (b - x) + (t - x) + x + none$

This gives:

$50 = (16 - x) + (41 - x) + x + 7$

Open brackets

$50 = 16 - x + 41 - x + x + 7$

$50 = 16 - x + 41 +7$

Collect like terms

$x = 16 - 50 + 41 +7$

$x = 14$

Hence, 14 students did both