SOLUTION: I really don't know know if this type of question belongs in this category. BDW, here's my question.
Zildijian's friends gave her a gift costing P240 for her sixteenth birthday.
Algebra.Com
Question 920010: I really don't know know if this type of question belongs in this category. BDW, here's my question.
Zildijian's friends gave her a gift costing P240 for her sixteenth birthday. If four more friends had contributed, the cost of each would be P3 less. How many friends bought the gift?
Found 2 solutions by ewatrrr, rothauserc:
Answer by ewatrrr(24785) (Show Source): You can put this solution on YOUR website!
n the number of friends buying the gift
= P3 |Multiplying thru by n(n+4) so as all denominators = 1
240(n+4) - 240n = 3n(n+4)
3n^2 + 12n - 960 = 0
n^2 + 4n - 320 = 0 (Tossing out the negative solution for unit measure)
(n+20)(n-16) = 0
n = 16 friends bought a gift
and...checking
240/16 - 240/20 = P15 - P12 = P3
Answer by rothauserc(4718) (Show Source): You can put this solution on YOUR website!
let x be the number of friends, y is money contributed by each friend
xy = 240
(x + 4)*(y - 3) = 240
solve first equation for y
y = 240/x
substitute for y in second equation
(x + 4)*(240/x - 3) = 240
(x + 4) * ((240 - 3x) / x) = 240
(-3x^2 + 228x +960)/x = 240 / 1
cross multiply fractions
-3x^2 + 228x +960 = 240x
-3x^2 - 12x + 960 = 0
use qudratic formula to solve for x
x = (12 + 108) / -6 = -20
x = (12 - 108) / -6 = 16
we want the positive value for x, therefore
16 friends bought the gift
RELATED QUESTIONS
I know this question has appeared before on here and it's kind of been semi-answered but... (answered by Theo)
Good evening, i’m so confused about this question. I don’t know if i will do the graphing (answered by josgarithmetic)
Hi, I don't know if this equation belongs here but I would like some help with this... (answered by math_tutor2020,ikleyn)
I am sorry, I do not really know what category this should be in.
My question is: Two... (answered by Tatiana_Stebko)
4. How many arrangements are there of Seven a’s, Eight b’s, Three c’s, Six d’s... (answered by venugopalramana)
A builder of tract homes reduced the price of a model by 15%. If the new price is... (answered by ikleyn,MathTherapy,greenestamps)
Will you please help me answer this question none of my friends or parents know what to... (answered by stanbon,josmiceli)
Factoring out Monomials THIS IS MY LAST QUESTION AND ILL PASS MY CLASS TOMMOROW
PLEASE... (answered by longjonsilver)
Assuming an alligator swallows stones with a mass 2.2 kg how much deeper, in millimeters, (answered by ikleyn)