**Question**

**Introduction**

The key to solving this is to find the total rate of work for Ahmad,
Kumar and Calvin. There is a
relationship Work = Rate ´ Time, similar to the relationship Distance
= Speed ´ Time, and you can use a similar triangle
mnemonic for it. For example if you
cover ‘R’ with your finger, you get the relation Rate = Work / Time. To organise your information, you may use a
table to tabulate the given data.

Do you believe “more hands make light work”? Or is it “too many cooks spoil the broth”? In real life, people may not work
harmoniously together, or work at the same rate (never getting tired). They may get distracted by Facebook, mobile
phones or office gossip. In school
mathematics problems, we assume that when people work together, we can just add
up their rates of work. Yes, it is quite
funny, but let us just assume.

**Solution**

**Ans:**10 days

**Commentary**

When we add
up the given rates, we get

It is
possble to do this question without the table, for example by taking the LCM of
the denominators and considering how many houses can the guys build in 60 days. However, the table is a good way of
organising information and you can solve the problem by considering the total
rate.^{1}/_{5}, which is the rate that 2 Ahmads, 2 Kumars and 2 Calvins would work. Unfortunately we do not have the clones. We just have one Ahmad, one Kuman and one Calvin. So we divide that by 2 to get^{1}/_{10}and this is their combined rate. This means that they can complete 1 house in 10 days.
H02. Use a diagram
/ model (including table)

H03. Make a
systematic list

H05. Work
backwards

H09. Restate
the problem in another way

H11. Solve part
of the problem

**Suitable Levels**

*****Primary School Mathematics

* other syllabuses that involve fractions
and ratios

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