Question:
A shop sells two types of pens at Rs. 10 and Rs. 15 each. If 50 pens are sold for Rs. 650, how many pens of Rs. 10 were sold?
A shop sells two types of pens at Rs. 10 and Rs. 15 each. If 50 pens are sold for Rs. 650, how many pens of Rs. 10 were sold?
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For mixture problems, set up the equation based on total cost or quantity and solve for the unknown.
Updated On: Jul 28, 2025
- 20
- 25
- 30
- 35
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The Correct Option is A
Solution and Explanation
To determine how many pens priced at Rs. 10 each were sold, let's follow these steps:
- Let the number of Rs. 10 pens be x.
- Let the number of Rs. 15 pens be y.
- From the problem, we know the total number of pens is 50, thus the equation x + y = 50.
- We also know the total sales amount is Rs. 650. Therefore, the equation for the total sales is 10x + 15y = 650.
Now, solve the equations:
- First, solve for y in terms of x using the total number of pens: y = 50 - x.
- Substitute y in the sales equation:
10x + 15(50 - x) = 650 - Simplify and solve for x:
10x + 750 - 15x = 650-5x + 750 = 650-5x = 650 - 750-5x = -100x = 20
Hence, the number of pens sold at Rs. 10 each is 20.
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