Page 151 - Start Up Mathematics_8 (Non CCE)

2 Ê 1 y+ ˆ 1 4 1 1 3x + 2 6x + 7
(d) 4 ( y - 1) - Á 2y - ˜ = y + (e) x + x = - 7 (f) =
x
3 Ë 3 ¯ 3 3 6 4 2x + 3 4x + 5
2. Three consecutive integers are such that when taken in increasing order and multiplied by 2, 3 and 4
respectively, add up to 74. Find the numbers.
3. The product of two consecutive numbers is greater than the square of the smaller by 30. Find the
numbers.
4. Rakesh is twice as old as Vivek. In 12 years time, their combined ages will be six times that of Vivek’s
present age. What are their present ages?
5. A two-digit number is such that the sum of its digits is 9. On adding 9 to the number, the digits are
reversed. Find the number.
1
6. There were some chocolates in a box. Santosh gave 1 th of the chocolates to Pinki, rd of the chocolates
4 3
to Poonam and 50 chocolates to Alpana. How many chocolates were there in the box?

Thinking Skills

1. From the table given alongside, find which equation x 2 4 6 8
represents the relation correctly.

1 1 y 150 200 250 300
(a) y = x +100 (b) y = x +100
25 2
(c) y = 2x + 100 (d) y = 25x + 100
2. There are some benches in a classroom. If 4 students sit on each bench, three benches are left vacant;
and if 3 students sit on each bench, 3 students are left standing. What is the total number of students in the
class?

3. Devesh’s school is 15 km from his home. He covers this distance in 3 hours, partly by walking and partly
by cycling. If he walks at 3 km/h and cycles at 9 km/h, how much distance does he cover by cycling?
4. Complete the magic square using linear equations so that the sum of each row, column and diagonal is
equal.

42 140 77
133 98

56 126
119 49 112

Values and Life Skills

1. Meenakshi has a locker in a bank. She has a total of ` 2,80,000 in her locker. The currency notes are in
the denomination of ` 50, ` 20 and ` 10. These currency notes are in the ratio 3 : 4 : 5. How many notes
of each denomination are there in her locker? Is it safe to share your locker’s password with anyone?
Why?
2. For a train journey, (20x + 50) passengers bought tickets costing ` 500 each and (30x – 20) passengers
bought tickets costing ` 750 each. If the train has a capacity of 480 passengers and was just full, find the
number of passengers for each category of ticket and also the total money paid for the ticket. Is it fair to
buy tickets illegally?
3. How much acid should be added to 400 mL of 15% acid solution to increase its strength to 32%? Suggest
2 steps to prevent the malice of acid attack on women.

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