Question
In a group, if 3 people with an average weight of 70 kg
leave, the average weight of the remaining group drops by 2 kg. However, if 4 people of average weight 68 kg leave, the average decreases by 2.5 kg. How many people were in the group initially?Solution
ATQ,
Let the number of people in group and average weight be 'n' and 'm' kg, respectively.
So,
mn - 3 × 70 = (n - 3) × (m - 2)
⇒ mn - 210 = mn - 2n - 3m + 6
⇒ 2n + 3m = 216 --------- (I)
And,
mn - 4 × 68 = (n - 4) × (m - 2.5)
⇒ mn - 272 = mn - 2.5n - 4m + 10
⇒ 2.5n + 4m = 282 -------- (II)
Now solving:
Multiply (I) by 4: 8n + 12m = 864
Multiply (II) by 3: 7.5n + 12m = 846
Subtracting:
0.5n = 18
⇒ n = 36
Where was the first meeting for Individual Satyagraha held in 1940 in Garhwal?
Who became the first bank to install an ATM on a train in India?
The Union Cabinet approved the establishment of a ₹1,000 crore Venture Capital Fund for which sector under IN-SPACe?
Which city won the "Best Public Transport System" award at the UMI Conference 2024?
Transparency International has released the Corruption Perceptions Index (CPI) 2021 in which India has been ranked at 85th spot and which country has to...
What is the name of the new automation software rolled out by the Defense Ministry of India for Defense Security Corps Personnel?
Tampara Lake which is going to be added in Ramsar sites is in which state?
The process of raising crops without using chemical fertilizers and pesticides or any other external material, Zero-budget natural farming (ZBNF), was i...
Income recognition and provisioning guidelines were introduced by RBI in-
Which amongst the following nations is not a member of G- 20?
Relevant for Exams:
