Need help understanding why this is the answer to this equation

• Feb 5th 2013, 10:49 AM
ollyrutts
Need help understanding why this is the answer to this equation
Hi there, would really appreciate some help in understanding why this is the answer to this equation.

Find the value of 2/3 (4+3q) when q = 4/5.

The answer given in the back of the book im working from is 4 4/15.

Now when i type the equation into my calculator i get 26/5.

I have been trying to work out why the answer is 4 4/15 and cant seem to quite get it.

Thanks Olly
• Feb 5th 2013, 11:46 AM
ollyrutts
Re: Need help understanding why this is the answer to this equation
• Feb 5th 2013, 12:08 PM
sakonpure6
Re: Need help understanding why this is the answer to this equation
I typed it in mine and i got 4 4/15. I think that your calculator does not do order of operations?

First thing you do is 3*(4/5)
Then you add 4 to it
Finally you multiply the sum you get which is 6 2/5 by 2/3 and you get 4 4/15
• Feb 5th 2013, 01:19 PM
ollyrutts
Re: Need help understanding why this is the answer to this equation

Ok so i think i got my head around it, without a calculator:

3*(4/5) = 3/1 x 4/5 = 12/5

12/5 = 2 2/5

2 2/5 + 4 = 6 2/5

6 2/5 = 32/5

32/5 x 2/3 = 64/15 = 4 4/15

Now is there a simpler way to do this without a calc or do you have to do all these steps.

Also my calculator is a Casio fx-991es, im not sure if it does order of operations. My calculator gives the final answer 64/15, should it give the answer as a simplified mixed number i.e 4 4/5?
• Feb 5th 2013, 02:57 PM
sakonpure6
Re: Need help understanding why this is the answer to this equation
this is how i would type this in my calculator: 2/3(4+3*4/5) and it works :D