Manju starts for her school at 8:16 a.m. on her bicycle. If she travels at a speed of 12 km/hr, then she reaches her school late by 7 minutes but on travelling at 18 km/hr, she reaches the school 10 minutes early . At what time does the school starts ?
Answers
Answer:
Manju starts for her school at 8:16 a.m. on her bicycle. If she travels at a speed of 12 km/hr, then she reaches her school late by 7 minutes but on travelling at 18 km/hr, she reaches the school 10 minutes early . The school starts at 9.00 a.m
Step-by-step explanation:
Let t be the time taken by Manju to reach the class on time, and x be the distance to school.
Speed = Distance /Time
When Manju arrives 7 minutes late the equation is given as:
x/12 = t + 7/60
x = 12(t + 7/60)
x = 12t + 1.4................i)
When Manju arrives 10 minutes early the equation is given by:
x/18 = t - 10/60 = t - 1/6
x = 18(t - 1/6)
x = 18t - 3...................ii)
Equating the two equations we have:
18t - 3 = 12t + 1.4
18t - 12t = 1.4 + 3
6t = 4.4
t = 4.4/6
t = 11/15 hours
In minutes it is equal to = 11/15 × 60 = 44 minutes
The school therefore starts at:
8.16 + 44 = 9.00 a.m