edited by
1,033 views

2 Answers

Best answer
1 votes
1 votes

Answer is A

Let the number of persons be x

$\frac{6500}{x}=\frac{6500}{x+15}+30$

$\frac{6500}{x}-\frac{6500}{x+15}=30$

$6500 *(\frac{1}{x}-\frac{1}{x+15})=30$$6500 *\frac{x+15-x}{x(x+15)}=30$

$x^{2}+15x-3250=0$ 

Roots of the equation $ax^2 + bx +c = 0$ are given by $\dfrac{-b\pm \sqrt{b^2-4ac}}{2a}.$ 

So, we get $ x = \dfrac{-15 \pm \sqrt{225 +13000}}{2} = \dfrac{-15 \pm 115}{2} =50, -65$

Number of persons cannot be negative. So, x = 50

selected by

Related questions

0 votes
0 votes
1 answer
2
Lakshman Bhaiya asked Apr 1, 2020
751 views
The simplified form of $\left[ \left ( \left( \dfrac{a+1}{a-1}\right)^2+3 \right)\div \left( \left( \dfrac{a-1}{a+1}\right)^2+3\right) \right] \div \left [\left( \dfrac{a...
0 votes
0 votes
1 answer
3
Lakshman Bhaiya asked Apr 1, 2020
724 views
The factors of $(x^{2}+4y^{2}+4y-4xy-2x-8)$ are:$(x-2y-4)(x-2y+2)$$(x-y+2)(x-4y-4)$$(x+2y-4)(x+2y+2)$None of these
1 votes
1 votes
2 answers
4
Lakshman Bhaiya asked Apr 1, 2020
762 views
If $a^{x}=b, b^{y}=c$ and $c^{z}=a$, then $xyz$ equals:$abc$$\dfrac{1}{abc}$$1$None
0 votes
0 votes
2 answers
5
Lakshman Bhaiya asked Apr 1, 2020
993 views
The minute hand is $10$ cm long. Find the area of the face of the clock described by the minute hand between $9$ a.m and $9:35$ a.m.${183.3\ cm^{2}}$${366.6\ cm^{2}}$${24...