It takes 6 hours to complete the work for both Lisa and Tom working together.
Step-by-step explanation:
step 1 :
Let us assume that,
Total work = 130 units (take a number that can be divisible by both 10 and 13)
step 2 :
Lisa completes the work in 10 hours.
Lisa's work per hour = total work / time taken to complete the work
= 130 / 10 = 13 units per hour
step 3 :
Tom completes the work in 13 hours.
Tom's work per hour = total work / time taken to complete the work
= 130 / 13 = 10 units per hour
step 4 :
Both Lisa and Tom can work per hour = 13 units + 10 units
= 23 units per hour
step 5 :
Working together can complete the total work in = total work / time taken to complete the work together
= 130 units / 23 units per hour = 5.65 (which is approximately 6 hours).
∴ Time taken by working together = 6 hours.
