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Math Question?
Can someone please help me with this question and explain to me how you came to your answer?
It was one of three questions I got wrong on a practice test.
Thanks for your help!
If 9 employees require 15 days to complete a task, how long would it take to do the same work if there were 3 additional employees?
Assume that all employees are equally efficient.
10
11.25
12
16
20
The second question I got wrong (and only number sequence question) was:
Each question of this type presents a series (list) of numbers and/or letters. Find the rule that has been used to produce this series; then use this rule to select the item (either a number or letter) which would follow at the end.
1 3 9 2 8 32 3
2 Answers
- PuzzlingLv 77 years agoFavorite Answer
PROBLEM 1:
The easiest way to figure these out is to calculate the amount of "employee-days" needed to complete the job.
If you have 9 employees and they take 15 days, that's the equivalent of 9 x 15 = 135 "employee-days".
Now if you had 1 person, it would take 135 days.
If you had 3 people it would take 45 days.
etc.
In your case, you have 12 people (9+3), so divide 135 by 12:
135 / 12
= 45 / 4
= 11 1/4
= 11.25 days
P.S. It makes sense that it would take less time to complete if you have more people.
PROBLEM 2:
Break the numbers into groups of 3:
1, 3, 9 --> rule, each number multiplied by 3
2, 8, 32 --> rule, each number multiplied by 4
3, ..., ... --> rule, each number multiplied by 5
Answer:
..., 3, 15, 75
- Kathleen KLv 77 years ago
Number of workers and time required to complete a job is INVERSELY proportional. Think about it: The more people working, the less time it will take to complete the job. As one quantity increases, the other decreases. As opposed to direct proportions that you're probably familiar with where you use fractions ("ratios") to set up the proportion, with inverse proportions, you multiply the quantities:
9 employees * 15 days = 12 employees * x days
9(15)/12 = x
x = 11.25 days
