Answer:
Step-by-step explanation:
Question (1). An alloy contains zinc and copper in the ratio of 7 : 9.
If the weight of an alloy = x kgs
Then weight of copper =
=
And the weight of zinc =
=
If the weight of zinc = 31.5 kg
31.5 =
x =
x = 72 kgs
Therefore, weight of copper =
= 40.5 kgs
2). i). 2 : 3 =
4 : 5 =
Now we will equalize the denominators of each fraction to compare the ratios.
=
Since,
Therefore, 4 : 5 > 2 : 3
ii). 11 : 19 =
19 : 21 =
By equalizing denominators of the given fractions,
And
Since,
Therefore, 19 : 21 > 11 : 19
iii).
=
Now we equalize the denominators of the fractions,
And
Since
Therefore, will be the answer.
IV).
Similarly,
By equalizing the denominators,
Similarly,
Since
Therefore,
V). If a : b = 6 : 5
And b : c = 10 : 9
Since a : b = 12 : 10
And b : c = 10 : 9
Since b = 10 is common in both the ratios,
Therefore, combined form of the ratios will be,
a : b : c = 12 : 10 : 9