Math

Problem:



(6 - 10) with working

Solution:

6) $ \frac{2}{5} \div \frac{1}{4} = \frac{2}{5} \times \frac{4}{1} = \frac{8}{5} = 1\frac{3}{5} $.

7)
$ 4.5 \times \frac{22}{22 + 23} =  4.5 \times \frac{22}{45} = 2.2 $
$ 4.5 \times \frac{23}{22 + 23} =  4.5 \times \frac{23}{45} = 2.3 $

8) $ y = 10 - 8x = 10 - 8 \times \frac{1}{2} = 10 - 4 = 6 $
9) The easiest way is to assume the middle two numbers are 6, now the sum of the two them is 12, the sum of the rest must be $ 8 \times 4 - 12 = 32 - 12 = 20 $, we can satisfy it with 1, 19.

So the four numbers are 1, 6, 6, 19.

10) $ x = \frac{4 \times 5 + 3}{2} = \frac{23}{2} = 11\frac{1}{2} $