Solved Questions on Length
1. The teacher is measuring the height of a girl, as shown in the figure. The height of the teacher is three feet less than the three times the height of the girl. What is the height of the teacher in inches?
a) 44 inches
b) 54 inches
c) 64 inches
d) 74 inches
Answer: b) 54 inches
Explanation: Height of the girl marked on the scale = 2.5 feet
According to the question,
The height of the teacher is three feet less than the three times the height of the girl.
Height of the teacher = (3 × Height of the girl) − 3
= (3 × 2.5) − 3
= 7.5 − 3
= 4.5 feet
Height of the teacher in inches = 4.5 feet
= (4.5 × 12) inches
= 54 inches
2. The length of car X is forty centimetres less than car Z and the length of car Y is fifty centimetres less than car Z. What is the length of car Y if the length of car X is 2 metres?
a) 1.7 m
b) 1.9 m
c) 2.1 m
d) 2.4 m
Answer: b) 1.9 m
Explanation: Length of car X = 2 m
= 2 × 100 cm
= 200 cm
The length of car X is forty centimetres less than car Z. Therefore, the length of car Z is forty centimetres more than car X.
Length of car Z = Length of car X + 40 cm
= (200 + 40) cm
= 240 cm
The length of car Y is fifty centimetres less than car Z.
Length of car Y = Length of car Z − 50 cm
= (240 − 50) cm
= 190 cm
= (190 ÷ 100) m
= 1.9 m
3. Anne and her aunt decided to go to the shopping mall. Anne travelled 3.2 kilometres to her aunt's home from her home. Then Anne and her aunt went to the shopping mall by travelling 4.8 kilometres. She and her aunt have purchased crockery sets, suits, sarees and jewellery. They returned using the same route. The next week, Anee went alone and travelled 6.7 kilometres directly to the shopping mall. What is the extra distance covered by Anee on the way to the shopping mall?
a) 1 kilometre 300 metres
b) 1 kilometre 600 metres
c) 1 kilometre 900 metres
d) 2 kilometres 300 metres
Answer: a) 1 kilometre 300 metres
Explanation: Distance travelled by Anne on the way to the shopping mall through Aunt’s home
= 3.2 + 4.8
= 8 km
Distance travelled by Anne on the way to the shopping mall directly = 6.7 km
Extra distance in meters covered by Anee on the way to the shopping mall
= (8 - 6.7) km
= 1.3 km
= 1.3 × 1000 m
= 1300 m
= 1000 m + 300 m
= 1 km + 300 m
= 1 km 300 m
4. The height of each building is decreased by 3.2 metres from right to left. If the height of building B is 750 m, what is the height of building E in hectometres?
a) 7.596 hectometres
b) 75.96 hectometres
c) 759.6 hectometres
d) 7596 hectometres
Answer: a) 7.596 hectometres
Explanation: Height of each building is decreased by 3.2 metres from right to left. Therefore, the height of each building is increased by 3.2 metres from left to right.
Height of building B = 750 m
Height of building E = Height of building B + 3.2 + 3.2 + 3.2
= 750 + 3.2 + 3.2 + 3.2
= 750 + 9.6
= 759.6 m
Height of building E in hectometres = (759.6 ÷ 100) hectometres
= 7.596 hectometres
5. An ant is 2 mm shorter than a lice. A spider is 4 mm shorter than a cockroach. A cockroach is 5 mm longer than an ant. What is the length of a lice in decimetres if the length of a spider is 2 cm?
a) 0.021 decimetres
b) 0.21 decimetres
c) 2.1 decimetres
d) 21 decimetres
Answer: b) 0.21 decimetres
Explanation: Length of a spider = 2 cm
= 2 × 10 mm
= 20 mm
A spider is 4 mm shorter than a cockroach. So, a cockroach is 4 mm longer than a spider.
Length of a cockroach = (20 + 4) mm = 24 mm
A cockroach is 5 mm longer than an ant. So, an ant is 5 mm shorter than a cockroach.
Length of an ant = (24 − 5) mm = 19 mm
An ant is 2 mm shorter than a lice. So, a lice is 2 mm longer than an ant.
Length of a lice = (19 + 2) mm = 21 mm
Length of a lice in decimetres = (21 mm ÷ 100) decimetres
= 0.21 decimetres
