please solve this question no. 11
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mohduzaif:
friend please come me answer
please give me answer
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2
Hope this helps.
Ask for any doubts at any step, and mention if you find any mistake.
Ask for any doubts at any step, and mention if you find any mistake.
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mujhe in sums me 1 doubt rehta hai
Dekho, question mein likha hai 4 pens and 4 pencil boxes ka combined cost 100 Rs. hai. So, we have taken cost of 1 pen as X, and cost of 1 pencil box as Y.
ok sir
Humein ye bhi given hai ke 3 pens ka cost 1 pencil box ke cost se 15 Rs. zyada hai.
Equation 1 ka case humein given tha so humne 4x + 4y = 100 ko apna 1st equation assume kara. Ab dusri equation banane ke liye humein dusre case ko represent karna tha, that is 3x = y + 15, it means 3 pens ka cost = 1 pencil box ka cost + 15 Rs.
sir en savalo me mujhe ek baat samaj nahi ati hai ki three times the cost of a pen is 15 rs jyada hai toh hum pencil me kyo plus Karna hai 15 rs hum pen ke use 15 rs minus bhi tho kar skate hai
Yes, isliye humne 3x = 4y + 15 ko baad mein 3x - 15 = 4y likha hai, which means 3 pens ka cost - 15 Rs. = 1 pencil box ka cost.
thank you sir
You're welcome.
Edit: In last comment I meant to write 3x = y + 15 and 3x - 15 = y.
Answered by
6
Question:
The cost of 4 pens and 4 pencil boxes is Rs. 100. Three times the cost of a pen is Rs. 15 more than the cost of a pencil box. Form the pair of linear equations for the above situation. Find the cost of a pen and a pencil box.
Solution:
Let the cost of a pen (in rupees) = x
Let the cost of a pencil box (in rupees) = y
According to question
4x + 4y = 100
x + y = 25 (Equation 1)
3x = y + 15
3x - y = 15 (Equation 2)
Adding Equation 1 and Equation 2
x + y + 3x - y = 25 + 15
4x = 40
x = 10
Putting value in Equation 1
x + y = 25
10 + y = 25
y = 25 - 10
y = 15
Therefore,
Cost of a pen = Rs. 10
Cost of a pencil box = Rs. 15
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