Question

5. A student bought some pens at 8 each and some pencils at 1.50 each. If the total
number of pens and pencils purchased is 16 and their total cost is 750, how many pens
did he buy?

Answer 1

Answer:

let number of pens be x and pencils be y.

then,8x+1.50y=750 ...1 equation.

and x+y=16 ....2 equation.

from 2 equation we get: x=16-y.

SUBSTITUTING THIS VALUE IN 1 EQUATION WE GET:y=41.056..

and then x=57.056..

Step-by-step explanation:

thanks for points.

Answer 2

Step-by-step explanation:

Given:-

A student bought some pens at 8 each and some pencils at 1.50 each.

The total number of pens and pencils is 16.

And their total cost = Rs.50

To Find:-

The number of pens bought by him.

Solution:-

Let the number of pens be x

And number of pencils be y

The total number of pens and pencils is 16.

$\sf \implies x + y = 16.....(i)⟹x+y=16.....(i)</p><p>Total cost = Rs.50$

$\sf \implies 8x + 1.5y = 50.....(ii)⟹8x+1.5y=50.....(ii)$

Multiply equation (i) with 8:-

$\sf \implies 8(x + y = 16)⟹8(x+y=16)$

$\sf \implies 8x + 8y = 128....(iii)⟹8x+8y=128....(iii)$

Equation (iii) - (ii)

$\sf \implies 8x + 8y - (8x + 1.5y) = 128 - 50⟹8x+8y−(8x+1.5y)=128−50$

$\sf \implies 8x + 8y - 8x - 1.5y = 78⟹8x+8y−8x−1.5y=78$

$\sf \implies 6.5y = 75⟹6.5y=75</p><p>[tex]\sf \implies y = \dfrac{75}{6.5}⟹y=6.575$

$\sf \implies y = 12⟹y=12$

Substitute y = 12 in equation (i)

$\sf \implies x + y = 16⟹x+y=16$

$\sf \implies x + 12 = 16⟹x+12=16$

$\sf \implies x = 4⟹x=4$

$\large\underline{\boxed{\therefore \textsf{\textbf{Total \: number \: of \: pens = 4}}}}$∴Total number of pens = 4