Page 152 - Start Up Mathematics_8 (Non CCE)

Some NCERT Textbook Questions

1. Solve the following equations.
3 17 y x 7
(a) x – 2 = 7 (b) + x = (c) 1.6 = (d) + 1 =
7 7 1.5 3 15
5 2 7
2. A rational number is such that when you multiply it by and add to the product, you get – 12 . What
2
3
is the number?
3. The organisers of an essay competition decide that a winner in the competition gets a prize of ` 100 and
a participant who does not win gets a prize of `25. The total prize money distributed is ` 3,000. Find the
number of winners, if the total number of participants is 63.
4. Solve the following equations and check your results.
4 5 26
(a) 5t – 3 = 3t – 5 (b) x = (x + 10) (c) 2y + = – y
5 3 3
5. One of the two digits of a two digit number is three times the other digit. If you interchange the digits
of this two-digit number and add the resulting number to the original number, you get 88. What is the
original number?
6. There is a narrow rectangular plot, reserved for a school, in Mahuli village. The length and breadth of the
plot are in the ratio 11 : 4. At the rate ` 100 per metre it will cost the village panchayat ` 75000 to fence
the plot. What are the dimensions of the plot?
7. Half of a herd of deer are grazing in the field and three fourths of the remaining are playing nearby. The
rest 9 are drinking water from the pond. Find the number of deer in the herd.
8. Solve the following equations.
3y + 4 –2 7y + 4 –4
(a) = (b) =
2 – 6y 5 y + 2 3
9. The ages of Hari and Harry are in the ratio 5 : 7. Four years from now the ratio of their ages will be
3 : 4. Find their present ages.

Exemplar Problems

1. If a and b are positive integers, then the solution of the equation ax = b has to be always:
(a) positive (b) negative (c) one (d) zero
5x 2x
2. If -= , then the numerical value of 2x – 7 is:
4
3 5
19 13 13
(a) (b) - (c) 0 (d)
13 19 19
3. Any value of the variable which makes both sides of an equation equal is known as a _________ of the
equation.
4. If x is an even number, then the next even number is 2(x + 1). (True/False)
5. Solve the following.

x 1 Ê 1ˆ 1 1
+
(a) - Á x - ˜ = ( x 1 +) (b) 3(5x – 7) + 2(9x – 11) = 4(8x – 7) – 111
2 4 Ë 3¯ 6 12
6. ` 13,500 are to be distributed among Salma, Kiran and Jenifer in such a way that Salma gets ` 1,000 more
than Kiran and Jenifer gets ` 500 more than Kiran. Find the money received by Jenifer.
7. Kaustabh had 60 flowers. He offered some flowers in a temple and found that the ratio of the number of
remaining flowers to that of flowers in the beginning is 3 : 5. Find the number of flowers offered by him
in the temple.
8. A steamer goes downstream and covers the distance between two ports in 3 h. It covers the same distance
in 5 h when it goes upstream. If the stream flows at 3 km/h, then find what is the speed of the streamer
upstream?

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