Question

1. Find the volume, the total surface area of a rectangular solid 6 m long, 4.5 m broad and 80 cm high.
2. Find the cost of 8 kg apples, if 7 kg of apples costs 315 rupees.
3. The total surface area of a cube is 726 square cm. Find it's volume.
4. What are rational numbers? Give ten examples.
5. Solve : 3x + 5 = 11.
please solve......... ​

Answer 1

Answer:

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Step-by-step explanation:

Q1.

length = 6 m

width = 4.5 m

hieght = 80 cm ,to convert this into cm we will divide =80/100=0.8 m

so the hieght is =0.8 m

solution

volume of a rectangle=length × width ×hieght

                                  V=6×4.5×0.8

                                    V =21.6

Q2.

apples= 7 kg

cost   =315 rs

cost of 1 kg apples=x

solution

x= 315÷7

one kg cost =45 rupees

so, 8 × 45 = 360is the cost of 8 kg apples

Total surface area of cube = 6 ( side )²

Q3.

∴ 6 ( side )² = 726

⇒ ( side )² = 726 / 6

⇒ ( side )² = 121

⇒ side = √ 121

⇒ side = 11 cm

Now,

Volume of cube = ( side )³

⇒ Volume = ( 11 × 11 × 11 ) cm³

⇒ Volume = 1331 cm³

Q4.

examples

1. 7/4

2. 1/100

3.1/2

4. 1/11

5. 5/8

6.17/5

7.11/4

8.6/10

9.3/4

10.1/4

Q5.

3x+5=11

3x=11-5

3x=6

x=6/3

x=3