Elvin reads 3/7 of the pages in his books, he has 56 pages left to read. how many pages has he read already

   He has already read 42 pages

Step-by-step explanation:

First, we need to find the total number of pages in the book

To do that, from the question we were told Elvin read 3/7 of the pages, if he read 3/7  of the pages, this implies that he has 4/7 pages left to read.

Let x = the total number of pages in the book

So the mathematical interpretation of this statement is;

4/7   of    x   =   56

4/7     ×     x    =    56

   = 56

cross multiply

4x   =    56  ×   7

4x   =  392

Divide both-side of the equation by 4

x   =   98

The total number of pages in the book is 98 pages

To get the number of pages read, we simply subtract the number of pages left to read from the total number of pages.

Number of pages read  =  Total number of pages - Number of pages        unread

Number of pages read  =    98   -     56  =   42

Therefore the number of pages he had already read is 42 pages

$450

step-by-step explanation:

first, you have to multiply 150x2=300

next, you have to add 150+300= 450

7,24

step-by-step explanation: