Some students planned a picnic. The budget for the food was 2400. As 8 of them failed to
join the party, the cost of the food for each member increased by ₹ 50. Find how many students
went to the picnic.
answer it quickly
Answers
Question :
Some students planned a picnic. the budget fof the food was ₹ 2400. As 8 of them failed to join the party, the cost of the food for each member increased by ₹ 50. Find how many students went to the picnic.
Solution :
Let,
➡ total no. of students = x
and
➡ cost of the food for each member = y
then,
➛ x y = 2400 ......eqn (1)
➛ x = 2400 / y ...... eqn (2)
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Now,
since 8 students failed to join the party
therefore,
➡no. of students = x - 8
also,
the cost of food is increased by ₹ 50
so,
➡increased cost of food for each = y + 50
then,
➛ ( x - 8 ) (y + 50 ) = 2400
➛ xy + 50x - 8y -400 = 2400
using eqn (1)
➛ 2400 + 50x -8y -400 = 2400
➛ 50 x - 8 y - 400 = 0
using eqn (2)
➛ 50 (2400/y) - 8y = 400
➛ ( 120000 / y ) - 8y = 400
multiplying by y both sides
➛ 120000 - 8y^2 = 400 y
rearranging the terms
➛ 8 y^2 + 400 y - 120000 = 0
dividing by 8 both sides
➛ y^2 + 50 y - 15000 = 0
splitting the middle term
➛ y^2 + 150 y - 100 y - 15000 = 0
➛ y ( y + 150 ) - 100 ( y + 150 ) =0
➛ ( y-100) (y+150) = 0
so,
y = 100 and y = -150
negative value will be ignored so we will take
y = 100
putting this value in eqn (2)
x = 2400 / 100
x = 24
Hence,
24 students went for picnic.
Answer:
Hence, number of students are 24.