Work Time

[Admin]

#15463

If it takes 12 students 50 minutes to inflate 200 helium balloons, how long will it take 7 students working at the same rate (to the nearest minutes)?

if it takes 12 people 50 minutes, then it would take one person 50 times longer:
50 × 12 = 600 minutes
600 ÷ 7 = 85.7 minutes (this will be 7 times quicker)
= 86 minutes

[Admin]

#18860

If 3 men take 2 days to dig a trench, how long would it take for 4 men?
3 × 2 = 6 days	Step 1: Find out how long it takes for one man to dig trench. This will be longer, by 3 times. 1 man will take 3 × 2 = 6 days
6 ÷ 4 = 1.5 days	Step 2: Find out how long the 4 men will take. Since there are more men now than just one, it will take shorter time, so we divide by how many men there are. 6 ÷ 4 = 1.5 days

[Admin]

#18861

If there is enough food to last 7 people 4 days, how many days would there be enough food for 3 people?
7 × 4 = 28 days	Step 1: Find out how long the food would last for just one person. This will be longer, by 7 times. 1 person would have enough for 7 × 4 = 28 days
28 ÷ 3 = 9.3 days	Step 2: Find out how long the food would last for 3 people. Since there are more people now, it will run out more quickly, so we divide by how many people there are. 28 ÷ 3 = 9.3 days

[Admin]

#18862

If 5 teachers need 13 hours to mark the maths papers, how long would it take only 4 teachers?
5 × 13 = 65 hours	Step 1: Find out how long it would take for just one teacher. This will be longer, by 5 times. 1 teacher would take 5 × 13 = 65 hours
6 ÷ 4 = 1.5 days	Step 2: Find out how long it would take 4 teachers. Since there are more teachers now, it will not take as long, so we divide by how many teachers there are. 6 ÷ 4 = 1.5 days

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