Question

Which of the following are not equal sets

a) (x:x is a letter from the word MADAM) and (x: x is a letter from the word DAM

b) (x:x is even number) and (x:x is a number divisible by 2}

c) {x: x is a square number) and (x:x is sum of first 'n' odd numbers, neN}

d) (x:x is a prime number, x<8) and (x:x is an odd number, x<8}​

Answer 1

$\sf\underline{Answer:}$

d is not equal set

$\sf\underline{Explanation:}$

a) {A, D, M } is equal to {D, A, M}

[elements should not be repeated in a set, so set of letters in MADAM is {A, D, M} ]

→

b) {2, 4, 6, 8...} is equal to {2, 4, 6, 8...}

→

c) {1, 4, 9, 16..} is equal to {1, 4, 9, 16..}

[Here, sum of first n odd numbers - 1, 1+3 = 4, 1+3+5 = 9, 1+3+5+7 = 16...., Therefore they are equal sets]

→

d) {2, 3, 5, 7} is not equal to {1, 3, 5, 7}