Step-by-step explanation:
Let the number of books of Physics be x . Then , No. of chemistry books =3.5x
Now , according to question :
x+3.5x=90
Or , 4.5x=90
Or , x=90/4.5
Or , x=20
Now ,
3.5x= 3.5×20
= 70
Therefore , there were 70 chemistry books and 20 physics books in that question bank.
The answer is 8.5
Hope this helped
Answer is 3x -24
Step by step
We perform distributive multiplication of the number outside the parentheses by the numbers inside the parentheses