Math Problem Statement

A group of friends went on a picnic and planned to spend ₹96 on eatables. As four of them did not turn up, the remaining friends had to pay ₹4 each extra. How many went on the picnic?

Solution

Let's break down the problem step by step:

  • The total cost of eatables is ₹96.
  • Initially, let the total number of friends be xx.
  • The initial contribution per person is 96x\frac{96}{x}.
  • However, 4 people did not turn up, so the number of people who actually went is x4x - 4.
  • The new contribution per person is 96x4\frac{96}{x - 4}.
  • Each person now pays ₹4 extra, which gives us the equation: 96x4=96x+4\frac{96}{x - 4} = \frac{96}{x} + 4

Now, let's solve the equation:

96x496x=4\frac{96}{x - 4} - \frac{96}{x} = 4

First, find a common denominator for the left side:

96(x)96(x4)x(x4)=4\frac{96(x) - 96(x - 4)}{x(x - 4)} = 4

Simplifying the numerator:

96x96x+384x(x4)=4\frac{96x - 96x + 384}{x(x - 4)} = 4 384x(x4)=4\frac{384}{x(x - 4)} = 4

Now, multiply both sides by x(x4)x(x - 4):

384=4x(x4)384 = 4x(x - 4)

Divide both sides by 4:

96=x(x4)96 = x(x - 4)

Expand the right side:

96=x24x96 = x^2 - 4x

Rearrange it to form a quadratic equation:

x24x96=0x^2 - 4x - 96 = 0

Solve using the quadratic formula:

x=(4)±(4)24(1)(96)2(1)x = \frac{-(-4) \pm \sqrt{(-4)^2 - 4(1)(-96)}}{2(1)} x=4±16+3842x = \frac{4 \pm \sqrt{16 + 384}}{2} x=4±4002x = \frac{4 \pm \sqrt{400}}{2} x=4±202x = \frac{4 \pm 20}{2}

This gives two possible solutions:

x=4+202=12orx=4202=8x = \frac{4 + 20}{2} = 12 \quad \text{or} \quad x = \frac{4 - 20}{2} = -8

Since xx must be positive, the total number of friends initially was x=12x = 12.

Thus, 12 friends were originally supposed to go on the picnic, but after 4 did not turn up, 8 friends went on the picnic.

Would you like a detailed explanation of any part, or do you have further questions?

Here are 5 related questions you can try:

  1. If 3 people didn’t turn up, how much more would each friend have to pay?
  2. What if the total amount spent was ₹120 instead of ₹96?
  3. How would the equation change if 5 people didn’t show up instead of 4?
  4. What if the friends initially planned to spend ₹96, but the cost increased to ₹120 at the picnic?
  5. What would the equation look like if 6 people dropped out instead of 4?

Tip: In problems like these, setting up an equation based on the changes (like an increase in cost per person) is a key strategy to solving them systematically!

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Word Problems

Formulas

Quadratic equation: ax^2 + bx + c = 0
Equation: (Total cost / remaining people) = (Total cost / original people) + Extra cost per person

Theorems

Quadratic Formula

Suitable Grade Level

Grades 8-10