Q15. In human blood, the ratio of white blood cells to red blood cells is 1 : 700 where 700 is given to the
nearest 100.
A man has 3 x 1013 red blood cells to one significant figure.
Calculate the minimum number of white blood cells in this man's blood.
Give your answer in standard form.
(Total 3 marks)

Amira is painting a rectangular banner 2 1/4 yards wide. the banner will have a blue background. amira has enough paint to cover 1 1/2 square yards of the wall. the school colors are blue and yellow, so amira wants to add yellow rectangles on the left and right sides of the blue rectangle. the yellow rectangles will each be 3/4 yards wide and the same height as the blue rectangle. what will be the total area of the two yellow rectangles?

Identify the expression equivalent to 4(x + x + 7) − 2x + 8 − 4 by substituting x = 1 and x = 2.

If it 8 inch candle burns at 7/10 inch per hour and a 6 inch candle burns at 1/5 inch per hour after how many hours would both candles be the same height