Tales by Dots and Lines Class 8 MCQ

Tales by Dots and Lines Class 8 MCQ

Tales by Dots and Lines Class 8 MCQ

Question 1.

As part of class project, Rekha needs to find the average age of her family members. Rekha writes her family member’s age as follows :

32, 28, 23, 17, 15

Which of these is the average age of members in Rekha’s family?

(a) 15

(b) 17

(c) 23

(d) 32

Answer:

(c) 23

Question 2.

The data below shows the number of balls a batsman played in the past 6 innings he played :

18, 36, 6, 12, 18, 36

What is the mean number of balls the batsman faced in an inning?

(a) 36

(b) 21

(c) 126

(d) 15

Answer:

(b) 21

Question 3.

What is the median of the data below?

42, 2, 54, 12, 20, 6, 30

(a) 12

(b) 2

(c) 54

(d) 20

Answer:

(d) 20

Question 4.

The line graph below shows the number of bikes sold at a store on each day of last week.

On which two days’ equal number of bikes were sold?

(a) Sunday and Monday

(b) Sunday and Tuesday

(c) Wednesday and Friday

(d) Monday and Wednesday

Answer:

(b) Sunday and Tuesday

Question 5.

The line graph below shows the value of Akhil’s laptop over the years.

Which of the following statements is not correct?

(a) The value of laptop decreases by ₹ 3000 in 2004-05.

(b) The value of laptop decreases by ₹ 1500 in 2001-02.

(c) The value of laptop decreases by ₹ 5800 in 2006-07.

(d) The value of laptop decreases by ₹ 4500 in 2005-06.

Answer:

(c) The value of laptop decreases by ₹ 5800 in 2006-07.

Case Study

Question 1.

Drug Concentrations A patient in a hospital receives an injection of penicillin. Her body gradually breaks down the concentration of the penicillin in such a way that after every one hour, the concentration remains 60% of the previous concentration.

(a) If the patient has been given a dose of 300 milli-grams (mg) of penicillin at 8.00 a.m., then fill in the blanks in the following table :

(b) The graph corresponding to the above table will be :

(c) Another patient has to take a dose of 80 mg of some other drug. The graph depicts the remaining concentrations of the drug after 1 day, 2 days, 3 days and 4 days.

At the end of the first day, the drug concentration was

(i) 6 mg

(ii) 12 mg

(iii) 25 mg

(iv) 32 mg

(d) What was the drug concentration at the end of the third day ?

(e) Approximately the drug concen¬tration is what per cent of the previous day ?

(i) 50%

(ii) 40%

(iii) 30%

(iv) 20%

Answer:

(a) 180 mg, 108 mg, 65 mg

(b) (ii)

(c) (iv)

(d) 5 mg (approx.)

(e) (ii)

Question 2.

Air above the Earth’s Surface

The air above the Earth’s surface is divided into different layers according to its temperatures at different heights above sea level as shown in the given graph.

(a) Temperature of air at 40 km above sea level is approximately

(i) 33°C

(ii) -33°C

(iii) 20°C

(iv)-20°C

(b) The highest temperature normally reached in the Thermosphere is

(i) 10°C

(ii) 60°C

(iii) 40°C

(iv) -60°C

(c) If the temperature is 40°C, then the height above the sea level is

(i) 110 km

(ii) 115 km

(iii) 120 km

(iv) 125 km

(d) If the temperature is -60°C, then the height above the sea level is

(i) 75 km

(ii) 77 km

(iii) 85 km

(iv) 98 km

(e) The lowest temperature normally reached in the Mesosphere is

(i) 0°C

(ii) -10°C

(iii) -50°C

(iv) -90°C

Answer:

(a) (iv)

(b) (ii)

(c) (iii)

(d) (iv)

(e) (iv)