Question
A driver covers a distance in three stages. In the first
'z - 50' km, he drives at 40 km/h, for the next 'z' km at 60 km/h, and the remaining 'z + 50' km at 50 km/h. If the overall average speed is 50 km/h, calculate 'z'.Solution
ATQ, Let the total distance covered is: (z−50)+z+(z+50)=3z The total time taken is the sum of the time for each segment: 
Then, Average Speed Equation: Average Speed= (Total Distance/Total Time) = 50 km/h 
Now, Set Up the Equation: 
Then, solve for 'z' Find a common denominator (600) and combine terms: 
Cross-multiply and solve: 1800z = 1850z - 7500 7500 − 50z = -7500 z = 150
In a lock-making factory, 10 percent of the total produced locks were found to be defective, and 80 percent of the non-defective locks were exported. ...
- Rohit purchased a mobile phone for Rs. 18,500 and sold it for Rs. 21,465. Find the percentage of profit he made.
The number of trees in a park increases by 12% every year. If the number of trees after 2 years will be 3,136, find the current number of trees in the p...
A man spends 72% of his income. If his income increases by 28% and his expenditure increases by 25%, then what is the percentage increase or decrease in...
- A person paid Rs. 13500 for a refrigerator after a single discount of 25%. If he had been given successive discounts of 15% and 15%, how much would he have...
Out of his total income, Rahul spent 25% on rent, 35% of the remaining income on groceries, and saved 60% of the income left after his expenses.
The price of a commodity has risen by 40%, leading to a 25% decrease in the quantity sold. What is the overall impact on total revenue?
- During an election, 5% of the total electorate didn’t cast their votes. The winning candidate secured 51% of the total votes and won by 1400 votes. Deter...
Income of A is twice the income of B. B and A spend 75% and 85% respectively of their incomes. Find the savings of A, if B saves Rs. 18000 in a month.
The earnings ratio of individuals 'P' and 'Q' stands at 5:3, respectively. 'P' manages to save 20% of their income, which is precisely 80% of what 'Q' s...
Relevant for Exams:
