# Can someone tell me where I have gone wrong the answer is ment to be 3.89

• Dec 30th 2012, 08:19 PM
Bairdy13
Can someone tell me where I have gone wrong the answer is ment to be 3.89
Cant seem to get 3.89
15.4+(a*5.6)-(11.8/2.5)+3(2+1.1)=34.67
15.4+(a*5.6)-(4.72)+(9.3)=34.67
15.4+(a*5.6)+4.58=34.67
(a+5.6)+19.98=34.67
a=(34.67-19.98)/5.6
a=2.623
Could someone also inform me what everyone uses to write the math on the forum?
Cheers
• Dec 30th 2012, 09:51 PM
jakncoke
Re: Can someone tell me where I have gone wrong the answer is ment to be 3.89
Its hard to say what went wrong without the question. As for your expression $15.4 + a*5.6 - \frac{11.8}{2.5} + 3(2 + 1.1) = 34.67$ indeed evaluates to a = 2.623

The math language is called latex.
http://mathhelpforum.com/latex-help/...-tutorial.html
• Dec 30th 2012, 10:38 PM
Wilmer
Re: Can someone tell me where I have gone wrong the answer is ment to be 3.89
Quote:

Originally Posted by Bairdy13
15.4+(a*5.6)-(11.8/2.5)+3(2+1.1)=34.67

Save steps and headaches; start this way:
5.6a = 34.67 - 15.4 + (11.8/2.5) - 3(2+1.1)
• Dec 31st 2012, 01:24 AM
Bairdy13
Re: Can someone tell me where I have gone wrong the answer is ment to be 3.89
Apologies the question was transpose and find the unknown term. (a)
15.4+(a*5.6)-(11.8/2.5)+3(2+1.1)=34.67 is how it is written in the book and their answer is 3.89
• Dec 31st 2012, 05:35 AM
HallsofIvy
Re: Can someone tell me where I have gone wrong the answer is ment to be 3.89
So on the left you have 5.6a+ (15.4- 11.8/2.5+ 3(2+ 1.1))= 5.6a+ (15.4- 4.72+ 3(3.1))= 5.6a+ (10.68+ 9.3)= 5.6a+ 19.98 and on the right 34.67: 5.6a+ 19.98= 34.67. Subtract 19.98 from both sides: 5.6a= 34.67- 19.98= 14.69. Now divide both sides by 5.6:
a= 14.69/5.6= 2.6232..., NOT 3.89.
• Dec 31st 2012, 06:21 AM
Bairdy13
Re: Can someone tell me where I have gone wrong the answer is ment to be 3.89
Thank you. As I thought. It seems there may be a few wrong answers in this basic math review sheet.