15. If [tex]\(\frac{5}{8}\)[/tex] of a rod is equal to 5 metres, what should be [tex]\(\frac{3}{4}\)[/tex] of the rod?

a. 5 m
b. 6 m
c. 9 m
d. 12 m

16. How long will a man take to walk 600 metres if he walks at a rate of 4 km per hour?

a. 9 minutes
b. 9 hours
c. 18 minutes
d. 4.5 minutes

17. A man can do [tex]\(\frac{7}{8}\)[/tex] of a piece of work in 35 days; how long will it take to do 60% of it?



Answer :

Sure! Let's solve each of the problems step-by-step.

### Problem 15:
If [tex]\(\frac{5}{8}\)[/tex] of a rod is equal to 5 metres, what is [tex]\(\frac{3}{4}\)[/tex] of the rod?

We know:
[tex]\[ \frac{5}{8} \text{ of the rod} = 5 \text{ meters} \][/tex]

To find the entire length of the rod:
[tex]\[ \text{Let the full length of the rod be } L \text{ meters}. \][/tex]
[tex]\[ \frac{5}{8}L = 5 \][/tex]
[tex]\[ L = 5 \div \frac{5}{8} \][/tex]
[tex]\[ L = 5 \times \frac{8}{5} \][/tex]
[tex]\[ L = 8 \text{ meters} \][/tex]

Now, to find [tex]\(\frac{3}{4}\)[/tex] of the rod:
[tex]\[ \frac{3}{4}L = \frac{3}{4} \times 8 = 6 \text{ meters} \][/tex]

Thus, [tex]\(\frac{3}{4}\)[/tex] of the rod is 6 meters. Therefore, the answer is:
[tex]\[ \boxed{6} \][/tex]

### Problem 16:
How long will a man take to walk 600 meters if his walking rate is 4 km per hour?

First, convert the walking rate from kilometers per hour to meters per minute:
[tex]\[ 4 \text{ km/hr} = 4 \times 1000 \text{ meters/hr} = 4000 \text{ meters/hr} \][/tex]
[tex]\[ 4000 \text{ meters/hr} = 4000 \div 60 \text{ meters/minute} = \frac{4000}{60} \text{ meters/minute} = 66.67 \text{ meters/minute} \][/tex]

Now, calculate the time taken to walk 600 meters:
[tex]\[ \text{Time} = \frac{600 \text{ meters}}{66.67 \text{ meters/minute}} \approx 9 \text{ minutes} \][/tex]

Therefore, the time taken to walk 600 meters is:
[tex]\[ \boxed{9 \text{ minutes}} \][/tex]

### Problem 17:
A man can do [tex]\(\frac{7}{8}\)[/tex] of a piece of work in 35 days; how long will it take to do 60% of it?

First, find the total amount of time required to complete the entire work:
[tex]\[ \text{Let the total work be } W. \][/tex]
[tex]\[ \frac{7}{8}W = \text{ work done in 35 days} \][/tex]
[tex]\[ \frac{7}{8}W = 35 \text{ days} \][/tex]
[tex]\[ W = 35 \div \frac{7}{8} \][/tex]
[tex]\[ W = 35 \times \frac{8}{7} \][/tex]
[tex]\[ W = 40 \text{ days} \][/tex]

Now, calculate the time to complete 60% of the work:
[tex]\[ \text{Time for 60% work} = 40 \times \frac{60}{100} \][/tex]
[tex]\[ = 40 \times 0.6 = 24 \text{ days} \][/tex]

Therefore, the man will take:
[tex]\[ \boxed{24 \text{ days}} \][/tex]

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