Given expression = [(3.537 - .948)² + (3.537 + .948)²] / [(3.537)² + (.948)²]
= [(a - b)² + (a + b)²] / (a² + b²)

Correct Option: D

Given expression = [(3.537 - .948)² + (3.537 + .948)²] / [(3.537)² + (.948)²]
= [(a - b)² + (a + b)²] / (a² + b²)

(Where a = 3.537 and b = 0.948)
= 2(a² +b²) / (a² +b²)
= 2

Given Expression = (6.5 x 4.7 + 6.5 x 5.3 ) / (1.3 x 7.9 - 1.3 x 6.9)
= [6.5 x (4.7 + 5.3 )] / [13 x (7.9 - 6.9)]
= (6.5 x 10) / (1.3 x 1)

Correct Option: D

Given Expression = (6.5 x 4.7 + 6.5 x 5.3 ) / (1.3 x 7.9 - 1.3 x 6.9)
= [6.5 x (4.7 + 5.3 )] / [13 x (7.9 - 6.9)]
= (6.5 x 10) / (1.3 x 1)
= 50

2/5 = 0.4 , 5/6 = 0.833, 11/12 = 0.916 and 7/8 = 0.875

Correct Option: B

2/5 = 0.4 , 5/6 = 0.833, 11/12 = 0.916 and 7/8 = 0.875
Clearly, the greatest fraction is 0.916, i, e . 11/12.

Let the length of lamppost = L m
Then,first part = L/3
and second part = (3/8) x L/3 = L/8
and third part = 6 m 50 cm = 6.50 m
First part + second part + Third part = length of lamppost

Correct Option: C

Let the length of lamppost = L m
Then,first part = L/3
and second part = (3/8) x L/3 = L/8
and third part = 6 m 50 cm = 6.50 m
First part + second part + Third part = length of lamppost
⇒ L/3 + L/8 + 6.5 = L
⇒ L - L/3 - L/8 =6.5
⇒ (24L - 8L - 3L)/24 = 6.5
⇒ 13L/24 = 6.5
∴ L = (65.x 24)/13 = 12 m

Let man's salary be Rs. N
Money spend on food =N/7
Money spends on clothing = (N - N/7) x 1/2 = (6N/7) x (1/2) =3N/7
Money spend on entertainment = (N - N/7 - 3N/7)/3 = (7N - 4N)/7 = N/7
Now, money left =600
⇒ N - N/7 - 3N/7 - N/7 = 600

Correct Option: C

Let man's salary be Rs. N
Money spend on food =N/7
Money spends on clothing = (N - N/7) x 1/2 = (6N/7) x (1/2) =3N/7
Money spend on entertainment = (N - N/7 - 3N/7)/3 = (7N - 4N)/7 = N/7
Now, money left =600
⇒ N - N/7 - 3N/7 - N/7 = 600
⇒ 7N - 5N/7 = 600
⇒ N = 600 x 7/2 = Rs. 2100
∴ Money spend on entertainment = 1/7 x 2100 = Rs. 300