Answer:
18).
Total mass of materials = 4.8kg
For gravel
55% of the materials are gravel
So we have
55/100 × 4.8 kg
= 2.64kg
For sand
30% of the materials are sand
We have
30/100 × 4.8
= 1.44kg
For cement
The remaining materials were cement so we add the masses of both the sand and gravel and subtract it from the total mass
That's
4.8 - (2.64 + 1.44)
4.8 - 4.08
= 0.72 kg
20).
She earns £ 800 per week
She receives a raise of 7.5% which is
100 + 7.5 = 107.5%
So we have
107.5 / 100 × £ 800
= £ 860
She now earns £ 860 per week
Hope this helps you
