Question 1
Suppose 6kg of salt contains crystals. How many crystals are there is(i) 7kg of salt (ii) 3.5 kg of salt?
Solution:
Weight of salt |
6 |
7 |
3.5 |
Crystals |
6x10^{7} |
x |
y |
(i) or or crystals
(ii) .
Question 2
A machine in a pepsi factory fills 680 bottles in 5hrs. How many bottles will it fill in 3 hrs?Solution:
Time |
5 |
3 |
Number of bottles |
680 |
x |
Â
Number of bottles = 408 bottles.
Question 12
If the weight of 25 precious stones is 50 grams. How many precious stones of the same type would weigh 4500 kilograms.Solution:
Number of stones |
25 |
x |
Weight of stones (in grams) |
50 |
4500 |
The number of stones and their weigh are directly proportion.
= 2250 stones
2250 stones will weigh 4500 kilograms.
Question 17
Mr X is making a wheel using spokes. He wants to fix equal spokes in such a way that the angles between any pair of convective spokes are equal. Help him by completing the following table.Solution:
Number of spokes |
3 |
6 |
9 |
12 |
15 |
Angle between a pair of consecutive spokes |
90 |
60 |
x_{1} |
x_{2} |
x_{3} |
Question 19
Â
Solution:
Number of hours |
6 |
4 |
Number of workers |
10 |
x |
.
Question 20
5 pipes are required to fill a petrol tank in 2 hour 20 minutes. How long will it take if only 4 pipes of the same type are used?
Solution:
Number of pies | 5 | 4 |
Time (in min) | 140 | x |
175 minutes=
2 hrs 91 min =
Number of hours required = 2 hrs 91 min.