Radha is preparing for a cycling race and practices daily. The first week she cycles 5 km every day. Class 7
mediumRadha is preparing for a cycling race and practices daily. The first week she cycles 5 km every day. Class 7
Question 1.
Radha is preparing for a cycling race and practices daily. The first week she cycles 5 km every day. Every week she increases the daily distance cycled by ‘z' km. How many kilometres would Radha have cycled after 3 weeks? Radha is preparing for a cycling race and practices daily. The first week she cycles 5 km every day.
Solution:
First week = 5 × 7 = 35 km.
Second week = (5 + z) × 7- = 35 + 7z
Third week = (5 + 2z) × 7 = 35 + 14z
After 3 weeks, Radha would have cycled
= 35 + 35 + 7z + 35 + 14z
= (3 × 35 + 21 z) km
= (105 + 21z) km. .
Question 2.
In the following figure, observe how the expression w + 2 becomes 4w + 20 along one path. Fill in the missing blanks on the remaining paths. The ovals contain expressions and the boxes contain operations. Class 7
Solution:
Question 3.
A local train from Yahapur to Vahapur stops at three stations at equal distances along the way. The time taken in minutes to travel from one station to the next station is the same and is denoted by t. The train stops for 2 minutes at each of the three stations. Class 7
(a) If t = 4, what is the time taken to travel from Yahapur to Vahapur?
(b) What is the algebraic expression for the time taken to travel from Yahapur to Vahapur?
[Hint : Draw a rough diagram to visualise the situation.]
Solution:
(a) Time taken = 3 × t + 2 × 3
= (3t + 6) minutes = 3 × 4 + 6
= 18 minutes at t = 4.
(b) Algebraic expression = 3t + 6.