To determine how long it takes Lola and Better to paint 36 rubber ducky bills together, we first need to calculate their individual painting rates.
Lola's rate is:
- 1 bill in 8 seconds, so her rate is \( \frac{1 \text{ bill}}{8 \text{ seconds}} = \frac{1}{8} \text{ bills per second} \).
Better's rate is:
- 1 bill in 10 seconds, so his rate is \( \frac{1 \text{ bill}}{10 \text{ seconds}} = \frac{1}{10} \text{ bills per second} \).
Next, we combine their rates to find the total rate of work when they work together: \[ \text{Combined rate} = \frac{1}{8} + \frac{1}{10} \]
To add these fractions, we need a common denominator. The least common multiple of 8 and 10 is 40: \[ \frac{1}{8} = \frac{5}{40}, \quad \frac{1}{10} = \frac{4}{40} \] Thus, adding the two rates together gives us: \[ \text{Combined rate} = \frac{5}{40} + \frac{4}{40} = \frac{9}{40} \text{ bills per second} \]
Now, to find the time taken to paint 36 bills, we use the formula: \[ \text{Time} = \frac{\text{Number of bills}}{\text{Combined rate}} = \frac{36 \text{ bills}}{\frac{9}{40} \text{ bills per second}} \]
Calculating this gives: \[ \text{Time} = 36 \times \frac{40}{9} = \frac{1440}{9} = 160 \text{ seconds} \]
Therefore, it will take them together 160 seconds to paint 36 red bills.