Given: The temperature of Delhi and Lucknow were in the ratio 3:5 in July and 2: 3 in August. The percentage increase in temperature from August to September is twice as from July to August for Delhi and same as for July to August for Lucknow.
Asked: If the ratio of the sum of the temperatures of these two cities in August and July was 5: 4, then answer the following questions.
July:-
Temperature of Delhi = 3x
Temperature of Lucknow = 5x
August: -
Temperature of Delhi = 2y
Temperature of Lucknow = 3y
The percentage increase in temperature from August to September is twice as from July to August for Delhi
(2y/3x - 1) = 2(z/2y -1)
(2y-3x)/3x = 2(z-2y)/2y = (z-2y)/y
y(2y-3x)/3x = (z-2y)
z = 2y + y(2y-3x)/3x
The percentage increase in temperature from August to September is same as for July to August for Lucknow.
(3y/5x-1) = (z/3y-1)
z = 9yˆ2/5x
September: -
Temperature of Delhi = 2y + y(2y-3x)
Temperature of Lucknow = 9yˆ2/5x
The ratio of the sum of the temperatures of these two cities in August and July was 5: 4
(2y+3y)/(3x+5x) = 5y/8x = 5/4
y = 2x
August: -
Temperature of Delhi = 2y = 4x
Temperature of Lucknow = 3y = 6x
September: -
Temperature of Delhi = 2y + y(2y-3x)/3x = 4x + 2x(4x-3x)/3x = 4x + 2x/3 = 14x/3
Temperature of Lucknow = 9yˆ2/5x = 9*4xˆ2/5x = 36x/5
Q1. What was the percentage increase in temperature of Lucknow from July to August?
6x/5x - 1 = 1/5 = 20%
Q2. What was the value of the ratio (Temperature of Lucknow in September/Temperature of Delhi in September)?
(36x/5)/(14x/3) = 36*3/5*14 = 54/35
Q3. If temperature of Delhi in August was 20°C then what was the sum of the temperatures of these two cities in September?
Temperature of Delhi in August = 2y = 4x= 20
y = 10; x = 5
Sum of temperatures of Delhi & Lucknow in September = 14x/3 + 36x/5 = 14*5/3 + 36*5/5 = 70/3 + 36 = 23 1/3 + 36 = 59 1/3