Gary bought a pen a book and a calculator. the book cost 2 times as much as the pen and the calculator cost $1 more than the book. he spent $16 altogether. what was the cost of the book?

A few things you're given:

b=book

p=pen

c=calculator

b + p + c = 16

Relationships in order to only use one variable:

2p=b

2p+1=c

Equation:

2p + p + 2p+1 = 16

Combining Like Terms/Simplifying and Solving:

5p + 1 = 16

5p = 15

p = 3

Remember the relationship between pen and book.

2p = b so...

2 (3) = $6.00! :)

4 + 5 7/9= 9 7/9

step-by-step explanation:

cross multiplying, we get :

⇒ (3) × (5) = (9) × (x)

⇒ 15 = 9x