# 8. Equations Involving Fractions

In this section, we can find the solution easily by multiplying throughout by the lowest common denominator.

### Example 1

An aquarium can be filled by one hose in 7 minutes and a second thinner hose in 10 minutes.

How long will it take to fill the tank if both hoses operate together?

### Example 2

For 2 resistors with resistances R1and R2 in parallel, the combined resistance R is given by:

1/R=1/R_1+1/R_2

For a particular circuit, the combined resistance R was found to be 4 ohms (Ω), and R1= 10 Ω. Find R2.

### Example 3

A car averaged 30 km/h going from home to work and 40 km/h on the return journey. If the total time for the two journeys is 50 minutes, how far is it from home to work?

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