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Activity Discussion Math Algebraic equation

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• # Algebraic equation

Posted by on June 24, 2023 at 5:09 pm

Ann went to a shop to buy 2 pens and 5 pencils. If the cost of 2 pens was 30 rupees and total amount of her purchase was 80 rupees. How much did each pen and pencil cost?

replied 3 months, 1 week ago 3 Members · 2 Replies
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Member
June 24, 2023 at 7:09 pm
1

Let, the cost of pen and pencil be x and y respectively (x>=0 , y>=0)

cost of 2 pens is Rs. 30 (Given)

<b class=””>∴ 2x=30

<b class=””><b style=”font-family: inherit; font-size: inherit; color: var(–bb-body-text-color);”> ⇒ <b style=”font-family: inherit; font-size: inherit; color: var(–bb-body-text-color);”>x=15

cost of 2 pens and 5 pencils is Rs. 80 <b style=”font-family: inherit; font-size: inherit; color: var(–bb-body-text-color);”>(Given)

∴ 2x+5y=80 ⟶eqn(i)

Putting the value of x=15 in eqn(i), we get

30+5y=80

<b style=”font-family: inherit; font-size: inherit; color: var(–bb-body-text-color); background-color: var(–bb-content-background-color);”>⇒ 5y=80-30

⇒ y=50/5

⇒ y=10

Hence, the cost of 1 pen is Rs. 15 and the cost of 1 pencil is Rs. 10.

Member
June 24, 2023 at 7:26 pm
0

Ann went to a shop to buy 2 pens and 5 pencils. If the cost of 2 pens was 30 rupees and total amount of her purchase was 80 rupees. How much did each pen and pencil cost?

Solution:

Let x be the cost of a pen.

Let y be the cost of a pencil.

The cost of 2 pens are 30 Rs.

So,the algebraic expression is

2x = 30

x = 30/2 = 15

The cost of a pen = 15 Rs

Ann purchase 2 pens and 5 pencils in total amount 80 Rs.

So, the algebraic expression is

2x+5y = 80

2*15+5y = 80

30+5y = 80

5y = 80-30

5y = 50

y = 50/5 = 10

The cost of a pencil = 10 Rs