Sunday, November 16, 2014

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Problems on Simplification


Q1. In a classroom, if 6 students per bench are assigned to accommodate all students, one more bench will be required. However, if 7 students are accommodate per bench, there would be a space left for 5 students.What is the number of students in the class ?
30 45
42 72
Answer: Option D
Solution:
Let the number of benches in the class be x.
Then, 6(x + 1) = 7x - 5
x = 11.
Hence, number of students in the class = 6 ( x + 1)
= 6 x 12
= 72.
Wrong Answer


Q2. If a - b = 3 and a2 + b2 = 29, find the value of ab.
10 12
15 18
Answer: Option A
Solution:
2ab = (a2 + b2) - (a - b)2
   = 29 - 9 = 20
=> ab = 10.
Wrong Answer


Q3. The price of 10 chairs is equal to that of 4 tables. The price of 15 chairs and 2 tables together is Rs. 4000. The total price of 12 chairs and 3 tables is
Rs. 3500 Rs. 3750
Rs. 3840 Rs. 3900
Answer: Option D
Solution:
Let the cost of a chair and that of a table be Rs. x and Rs. y respectively.
Then, 10x = 4y   or   y = 5 x.
2
.'.  15x + 2y = 4000
=>  15x + 2 x 5 x = 4000
2
=>  20x = 4000
.'.  x = 200.
So, y = ( 5 x 200 ) = 500.
2
Hence, the cost of 12 chairs and 3 tables = 12x + 3y
    = Rs. (2400 + 1500)
    = Rs. 3900.
Wrong Answer


Q4. 5.8 ×2.5 + 0.6 ×6.75 + 139.25= ?
157.30 157.80
158.40 None
Answer: Option B
Solution:
Given exp. = 14.5 + 4.05 + 139.25
= 157.80.
Wrong Answer


Q5. On a sports day, if 30 children were made to stand in a column, then 16 columns could be formed. If 24 children were to stand in a column, then how many columns could be formed?
20 22
29 30
Answer: Option A
Solution:
Total number of children = (30 x 16)
= 480.

Number of columns of 24 children each
= (480 /24)
=20.
Wrong Answer

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