10 pens cost £4.00 find the cost of 7 pens

2 answers:

5 0

The answer is £2.80. To find the cost of 1 pen, you divide £4 (all 10 pens) by 10 which gives you 40p. To find 7 pens, you multiply 40p (1 pen) by 7. £0.40 x 7 = £2.80

Nina [5.8K]4 years ago

3 0

Well, the first thing we need to do is divide 10 by 4. These teo numbers are the number of pens, and cost of them. So,
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10 / 4 = 2.5
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Now we have to use the answer we got, 2.5 which is the cost of 1 pen, and multiply it by 7.
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2.5 x 7 = 17.5
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This means that 7 pens cost £17.5

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4 years ago

Read 2 more answers

A jumbo crayon is composed of a cylinder with a conical tip. The cylinder is 12 cm tall with a radius of 1.5 cm, and the cone ha

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Answer:

Part 1) The lateral area of the cone is $LA=2\pi\ cm^{2}$

Part 2) The lateral surface area of the cylinder is $LA=36\pi\ cm^{2}$

Part 3) The surface area of the crayon is $SA=41.50\pi\ cm^{2}$

Step-by-step explanation:

Part 1) Find the lateral area of the cone

The lateral area of the cone is equal to

$LA=\pi rl$

we have

$r=1\ cm$

$l=2\ cm$

substitute

$LA=\pi (1)(2)$

$LA=2\pi\ cm^{2}$

Part 2) Find the lateral surface area of the cylinder

The lateral area of the cylinder is equal to

$LA=2\pi rh$

we have

$r=1.5\ cm$

$h=12\ cm$

substitute

$LA=2\pi (1.5)(12)$

$LA=36\pi\ cm^{2}$

Part 3) Find the surface area of the crayon

The surface area of the crayon is equal to the lateral area of the cone, plus the lateral area of the cylinder, plus the top area of the cylinder plus the bottom base of the crayon

Find the area of the bottom base of the crayon

$A=\pi[r2^{2}-r1^{2}]$