Sean read 15 of a book in = 112 hours,
so, 1 of a book in = 112/15
Now, 12 of a book would be: 112/15 * 12 = 112/5 * 4 = 89.6
89.6 = 89 6/10 = 89 3/5
In short, Your Answer would be 89 3/5 hours
Hope this helps!
It's 7.4 because the 3 doesn't round the 4 up.
ANSWER

EXPLANATION
To find the expression that is equivalent to

we must first expand

Then we rearrange to find the required expression.
So let's get started.

We expand the parenthesis on the right hand side to get,

We expand again to obtain,

Let us group the cubed terms on the right hand side to get,


We make the cubed terms the subject,

We factor to get,

We expand the bracket on the left hand side to get,

We finally simplify to get,
So the question says:
____ + ____ = 18
____ * ____ = 77
so the answer is 7 and 11 :)))
lets check it:
7 + 11 = 18
7 * 11 = 77
I hope this is helpful
have a nice day