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Some Students Planned a Picnic. the Budget for Food Was Rs. 500. But, 5 of Them Failed to Go and Thus the Cost of Food for Each Member Increased by Rs. 5. How Many Students Attended the Picnic? - CBSE Class 10 - Mathematics

ConceptSolutions of Quadratic Equations by Factorization

Question

Some students planned a picnic. The budget for food was Rs. 500. But, 5 of them failed to go and thus the cost of food for each member increased by Rs. 5. How many students attended the picnic?

Solution

Let students planned a picnic.

Then, the share of each student = 500/x

According to question, 5 students fail to go picnic, then remaining students = (x - 5).

Therefore, new share of each student 500/(x-5)

It is given that

500/(x-5)-500/x=5

(500x-500x+2500)/((x-5)x)=5

2500/(x^2-5x)=5

2500 = 5(x2 - 5x)

2500/5=x^2-5x

500 = x2 - 5x

x2 - 5x - 500 = 0

x2 + 20x - 25x - 500 = 0

x(x + 20) - 25(x + 20) = 0

(x + 20)(x - 25) = 0

x + 20 = 0

x = -20

Or

x - 25 = 0

x = 25

Because cannot be negative.

Thus, the total numbers of students attend a picnic

= x - 5

= 25 - 5

= 20

Therefore, the total numbers of students attend a picnic be x = 20.

Is there an error in this question or solution?

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Solution Some Students Planned a Picnic. the Budget for Food Was Rs. 500. But, 5 of Them Failed to Go and Thus the Cost of Food for Each Member Increased by Rs. 5. How Many Students Attended the Picnic? Concept: Solutions of Quadratic Equations by Factorization.
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