Math Problem Statement

Two water taps together can fill a tank in 9 3/8 hours. The tap of larger diameter takes 10 hours less than the smaller one to fill the tank separately. Find the time in which each tap can separately fill the tank.

Solution

We are given the following information:

  • Two taps together can fill a tank in 9389 \frac{3}{8} hours.
  • The larger tap takes 10 hours less than the smaller one to fill the tank.

We need to find the time it takes for each tap (larger and smaller) to fill the tank separately.

Step 1: Convert the mixed fraction

9389 \frac{3}{8} hours can be converted to an improper fraction: 938=758 hours9 \frac{3}{8} = \frac{75}{8} \text{ hours}

Step 2: Define variables

Let:

  • tt be the time taken by the smaller tap to fill the tank on its own.
  • The larger tap takes t10t - 10 hours to fill the tank.

The rate of work (portion of the tank filled per hour) for each tap is:

  • Smaller tap: 1t\frac{1}{t} of the tank per hour.
  • Larger tap: 1t10\frac{1}{t - 10} of the tank per hour.

Together, they fill 1t+1t10\frac{1}{t} + \frac{1}{t - 10} of the tank per hour. According to the problem, they fill the tank in 758\frac{75}{8} hours together, so the rate of work is: 1t+1t10=875\frac{1}{t} + \frac{1}{t - 10} = \frac{8}{75}

Step 3: Set up the equation

Now, let's solve the equation: 1t+1t10=875\frac{1}{t} + \frac{1}{t - 10} = \frac{8}{75}

Multiply both sides by 75t(t10)75t(t - 10) to eliminate the denominators: 75(t10)+75t=8t(t10)75(t - 10) + 75t = 8t(t - 10)

Simplify: 75t750+75t=8t280t75t - 750 + 75t = 8t^2 - 80t 150t750=8t280t150t - 750 = 8t^2 - 80t 8t2230t+750=08t^2 - 230t + 750 = 0

Step 4: Solve the quadratic equation

We can solve the quadratic equation 8t2230t+750=08t^2 - 230t + 750 = 0 using the quadratic formula: t=(230)±(230)24(8)(750)2(8)t = \frac{-(-230) \pm \sqrt{(-230)^2 - 4(8)(750)}}{2(8)} t=230±529002400016t = \frac{230 \pm \sqrt{52900 - 24000}}{16} t=230±2890016t = \frac{230 \pm \sqrt{28900}}{16} t=230±17016t = \frac{230 \pm 170}{16}

So we have two possible solutions: t=230+17016=40016=25ort=23017016=6016=3.75t = \frac{230 + 170}{16} = \frac{400}{16} = 25 \quad \text{or} \quad t = \frac{230 - 170}{16} = \frac{60}{16} = 3.75

Step 5: Interpret the results

The time t=3.75t = 3.75 hours is not valid because the larger tap would take negative time. Therefore, the valid solution is: t=25 hourst = 25 \text{ hours}

Thus:

  • The smaller tap takes 25 hours to fill the tank.
  • The larger tap takes 2510=1525 - 10 = 15 hours to fill the tank.

Final Answer:

  • The smaller tap fills the tank in 25 hours.
  • The larger tap fills the tank in 15 hours.

Would you like further clarification on any part of the solution?

Here are 5 related questions:

  1. What is the formula for solving work rate problems?
  2. How would the solution change if both taps worked at the same rate?
  3. Can this problem be solved graphically? If so, how?
  4. How do you solve quadratic equations by factoring instead of the quadratic formula?
  5. How can you verify the solution once the times are found?

Tip: For work problems, always start by defining the rates for each worker and combine their rates for joint work.

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Math Problem Analysis

Mathematical Concepts

Algebra
Work and Time
Quadratic Equations

Formulas

Quadratic equation formula: ax^2 + bx + c = 0
Work formula: 1/t + 1/(t - 10) = 1/time together

Theorems

Quadratic formula

Suitable Grade Level

Grades 8-10