Problem Solving

[unavailable4now]

I have been struggling with these types of questions as you can see i have got them wrong (i have loads more of these questions) and i don't know the formula if there is. Please Help! Really urgent! I have an 11+ exam in a few days. Help! Help!?

 

[topsquark]

Please post any efforts you have made. It will help us help you find where you may have gone wrong.

In general the first thing that most students get confused about is that the don't actually define variables. For instance, for the first problem:
Let x be the number of 5 pence coins and y be the number of 50 pence coins. Then
5x + 50y = 2205
and
y = 2x

To solve this we know that y = 2x and this will be true in the first equation as well, so 5x + 50(2x) = 2205. Now solve for x.

Practically all of these types of word problems can be solved in this way.

-Dan

 

[unavailable4now]

Thanks