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insens350 [35]
3 years ago
5

Plssssss help number 18 and 20​

Mathematics
2 answers:
weqwewe [10]3 years ago
6 0

Answer:

<h2>18).</h2>

Total mass of materials = 4.8kg

<u>For</u><u> </u><u>gravel</u>

55% of the materials are gravel

So we have

55/100 × 4.8 kg

= 2.64kg

<u>For</u><u> </u><u>sand </u>

30% of the materials are sand

We have

30/100 × 4.8

= 1.44kg

<u>For</u><u> </u><u>cement</u>

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

<h2>20). </h2>

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

Xelga [282]3 years ago
5 0

Step-by-step explanation:

1)of 4.8kg concrete 55% is gravel,30% is sand and 15% is cement.

percent=Rate*Base

Pgravel=55%*4.8kg

Pgravel=2.64kg

Psand=30%*4.8kg

Psand=1.44kg

Pcement=15%*4.8kg

Pcement=0.72kg

2)percent=Rate*Base

percent=7.5%*£800

percent=60£

total earn=60£ + £800

total earn=£860

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Variable<em> y </em>represent the number of liters of the 90% solution.

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