Question

Which of these is in proportion?

i) 15, 45, 40, 120

ii) 4,6,11,12

iii) 1,2,3,4
iv)2,3,4,5
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Answer 1

Answer:

a

Step-by-step explanation:

• 15,45,40,120 are in proportion
• as 15×120 = 1800
• and 45×40=1800 too

Answer 2

Answer:

SOLUTION:

i) 15,45,40,120

we have 15,45,40,120

ratio of 15 to 45=\frac{15}{45}=\frac{15\div15}{45\div15}=\frac{1}{3}=1:3

45

15

=

45÷15

15÷15

=

3

1

=1:3

[HCF OF 40 and 15, 45 is 15]

ratio of 40 to 120=\frac{40}{120}=\frac{40\div40}{120\div40}=\frac{1}{3}=1:3

120

40

=

120÷40

40÷40

=

3

1

=1:3

[HCF of 40 and 120 is 40]

here, 15:4=40:120=1:3

ii) 33, 121,9,96

we have 33,121,9,96

ratio of 33 to121 = \frac{33}{121}=\frac{33\div11}{121\div11}=\frac{3}{11}

121

33

=

121÷11

33÷11

=

11

3

ratio of 9 and 96= \frac{9}{96}=\frac{9\div3}{96\div3}=\frac{3}{32}

96

9

=

96÷3

9÷3

=

32

3

[HCF of 9 and 96 is 3]

here, 3:11\ne3:323:11



=3:32

i.e\ 33:121\ne9:96i.e 33:121



=9:96

therefore, 31,121,9 and 96 are not in proportion.

iii) 24,28,36,48

ratio of 24 and 28 is \frac{24}{28}=\frac{24\div4}{28\div4}=\frac{6}{7}=6:7

28

24

=

28÷4

24÷4

=

7

6

=6:7

[HCF of 36 and 48 is 12]