Any number from 21-98 is between 20 and 99.
1/4 time 1/4 equals a half...or you can think about it as 25 plus 25 equals 50, (1/2 of a dollar)
Let

denote the number of minutes spent brushing his teeth, and let

be the mean and

the standard deviation for this distribution.

The z-score corresponding to this probability is approximately

, which means

Next, (note the sign change)

The corresponding z-score is approximately

, so you have

Solving the two equations for

and

, you'll find that the mean is approximately

and the standard deviation is approximately

.
they offer a lot of discounts prety much
Hi there!
Let's break this down:
Two times a number = 2n
Increased by 5 = + 5
is 15 - = 15
Total equation:
2n + 5 = 15
Solving:
2n + 5 = 15
2n = 10
n = 5
Hope this helps!! :)
If there's anything else that I can help you with, please let me know!