1. an alloy contains zinc and copper in the ratio of 7:9 find weight of copper of it had 31.5 kgs of zinc. 2. compare the following ratios

i) 2:3 and 4:5
ii) 11:19 and 19:21
iii) ½ : ⅓ and ⅓ : ¼
iv ) 1⅕ : 1⅓ and ⅖ : 3/2

v) if a : b = 6:5 and b:c = 10:9, find a:c

vi) if x : y = ⅙:⅛ and y : z = ⅛: ⅒, find X : z

sorry many questions

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

justin bieber ml.

there is only one way to arrange all the eight relative to each other because they are not distinct. we have

now there are nine places to place an (and not more than one in one place).   because we have four symbols, we need to choose four of these nine places to insert an . order does not matter because the are not distinct.

thus there are 1 · c(9,4) ways, or, if we calculate it,

thus there are 126 ways to form such "words."