Question

After reading 80% of her e-mails in her inbox, Danette still has M unread emails. Which of the following expressions could represent the number of e-mails Danette had in her inbox before she started reading?

Answer 1

m/(1 - .8)

Explanation:

She read 80% of her emails, which is .8 of the total. So her unread emails would be 100% - 80% = 1 - .8

that means me can be written as:

m = (1 - .8)t

where t is the total

If we solve for t, we get:

t = m/(1 - .8)

Answer 2

Answer with explanation:

Let number of emails in Danette inbox before she started Reading= x

Number of emails Read =80% of the email

Number of emails left after reading 80% of the emails =M

A.T.Q

`\rightarrow x-(80x)/(100)=M\\\\\rightarrow (100x-80x)/(100)=M\\\\\rightarrow (20x)/(100)=M\\\\ \rightarrow x=(100M)/(20)\\\\x=5 M`

Number of emails in Danette inbox before she started Reading =5 M