# Math Help - Ratio, radius and algebra

1. ## Ratio, radius and algebra

Question 1:
two girls share £24.80 in the ratio of 3:5
work out the difference between the larger share and the smaller share.

Question 2:
A circle has a radius of 5cm.

Work out the area of the circle
give your answer correct to 1 decimal place
give the units in your answer

Question 3:
Ruth says that 7x + 2x - 5 is an equation
ruth is wrong, explain why.

thanks in advance, if you explain how you do the question aswell that would be appreciated.

2. Originally Posted by jedsterg
Question 1:
two girls share £24.80 in the ratio of 3:5
work out the difference between the larger share and the smaller share.
Divide the money into (3+5) parts. Then the larger part of the money is $\frac58 \cdot 24.80$ and the smaller part is $\frac38 \cdot 24.80$.

To answer your question calculate:

$\frac58 \cdot 24.80 - \frac38 \cdot 24.80 = 24.80 \left(\frac58 - \frac38\right) = \frac14 \cdot 24.80 = 6.20$
Question 2:
A circle has a radius of 5cm.

Work out the area of the circle
give your answer correct to 1 decimal place
give the units in your answer
Use the formula to calculate the area of a circle: $a = \pi r^2$

With your question the unit of the area is $cm \cdot cm = cm^2$
Question 3:
Ruth says that 7x + 2x - 5 is an equation
ruth is wrong, explain why.
There must be an equal sign which seperates the 2 sides of an equation. In your case you have a term.