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प्रश्न
Some students planned a picnic. The budget for the food was Rs. 480. As eight of them failed to join the party, the cost of the food for each member increased by Rs. 10. Find how many students went for the picnic.
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उत्तर
Let x students planned a picnic.
Then, the share of each student `= 480/x`
According to question, 8 students fail to go picnic, then remaining students = (x − 8).
Therefore, new share of each student `480/(x-8)`
It is given that
`480/(x-8)-480/x=10`
`(480x-480(x-8))/(x(x-8))=10`
`(480x+3840-480)/(x^2-8x)=10`
`3840/(x^2-8x)=10`
`3840/10 = x^2 - 8x`
384 = x2 − 8x
x2 − 8x − 384 = 0
x2 + 16x − 24x − 384 = 0
x(x + 16) − 24(x + 16) = 0
(x + 16) (x − 24) = 0
x + 16 = 0
x = −16
Or
x − 24 = 0
x = 24
Because x cannot be negative.
Thus, the total numbers of students attend a picnic
= x − 8 = 24 − 8 = 16
Therefore, the total numbers of students attend a picnic be x = 16
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