Algebraic Expressions Practice – 12 Questions with Answers | Class 7 & 8 Maths

12 New Questions on Algebraic Expressions

Easy Level (1–4)

Q1. A notebook costs ₹m and a folder costs ₹n. Write an expression for the cost of 3 notebooks and 2 folders.
Q2. A bottle contains x litres of water. If 3 litres are added, what is the new quantity?
Q3. A taxi charges a fixed rate of ₹50 plus ₹r per km. Write the expression for a ride of 10 km.
Q4. The length of a rectangle is (l + 5) and the breadth is b. Write the expression for its perimeter.


Medium Level (5–8)

Q5. A fruit seller sells apples at ₹8 each and bananas at ₹3 each. Write an expression for the cost of p apples and q bananas.
Q6. A box contains (4k + 3) red balls and (2k – 1) blue balls. Write the expression for the total number of balls.
Q7. A toy costs ₹t. If 5 toys are bought and a discount of ₹20 is applied, write the expression for the total bill.
Q8. A subscription service charges ₹s per month and a one-time joining fee of ₹300. Write an expression for 12 months.


Higher Level (9–12)

Q9. A shopkeeper increases the price of an item costing ₹x by 15%. Write the new price.
Q10. A pipe fills a tank in (a + 3) minutes, but a second pipe empties it in (a – 1) minutes. Write an expression for the net time taken (in fraction form).
Q11. Write and simplify the expression:
(4p+3q)(2pq)+5(4p + 3q) – (2p – q) + 5(4p+3q)–(2p–q)+5
Q12. A journey consists of 2 parts: the first part covers (3d + 5) km and the second part covers (2d – 1) km. Write an expression for the total distance.

ANSWER KEY — Algebraic Expressions (12 Questions)


Easy Level (1–4)

Q1. Expression for 3 notebooks and 2 folders

Total Cost=3m+2n\text{Total Cost} = 3m + 2nTotal Cost=3m+2n


Q2. New quantity of water

x+3x + 3x+3


Q3. Taxi fare for 10 km

50+10r50 + 10r50+10r


Q4. Perimeter of rectangle

Length = l+5l + 5l+5, Breadth = bbbPerimeter=2[(l+5)+b]=2(l+b+5)\text{Perimeter} = 2[(l + 5) + b] = 2(l + b + 5)Perimeter=2[(l+5)+b]=2(l+b+5)


Medium Level (5–8)

Q5. Cost of apples and bananas

8p+3q8p + 3q8p+3q


Q6. Total number of balls

(4k+3)+(2k1)=6k+2(4k + 3) + (2k – 1) = 6k + 2(4k+3)+(2k−1)=6k+2


Q7. Total bill after discount

5t205t – 205t−20


Q8. Subscription cost for 12 months

12s+30012s + 30012s+300


Higher Level (9–12)

Q9. New price after 15% increase

Increase = 0.15x0.15x0.15xNew Price=x+0.15x=1.15x\text{New Price} = x + 0.15x = 1.15xNew Price=x+0.15x=1.15x


Q10. Net time expression (fraction form)

Filling time = a+3a + 3a+3
Emptying time = a1a – 1a−1

Net time (difference between rates):Net Rate=1a+31a1\text{Net Rate} = \frac{1}{a+3} – \frac{1}{a-1}Net Rate=a+31​−a−11​


Q11. Simplify (4p+3q)−(2p−q)+5(4p + 3q) – (2p – q) + 5(4p+3q)−(2p−q)+5

Expand:4p+3q2p+q+54p + 3q – 2p + q + 54p+3q−2p+q+5

Combine like terms:(4p2p)+(3q+q)+5=2p+4q+5(4p – 2p) + (3q + q) + 5 = 2p + 4q + 5(4p−2p)+(3q+q)+5=2p+4q+5

Final Answer:2p+4q+52p + 4q + 52p+4q+5


Q12. Total distance

(3d+5)+(2d1)=5d+4(3d + 5) + (2d – 1) = 5d + 4(3d+5)+(2d−1)=5d+4

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