Question
The average weight of a class of 25 student is 60 KG. If
X is student joined the class, than the average weight of whole class increases by (2X – 7)Kg. Find the value of X if the weight of whole class increases by 390 KG.Solution
Sum of weights of 25 student = 25*60 = 1500 kg Sum of the weights of (25+x)(60+2x-7) = {(25+x)(53+2x)} kg As per the question (25+x)(53+2x)-1500 = 390 (25+x)(53+2x) = 1890 2x² + 103x – 565 = 0 X= 5 or (-113/2) Student since the number of student cannot be negative. So our answer will be 5.
- Statements: Z = Y ≥ X > W, Q > O = P ≥ I, W ≥ V ≥ U = Q - Conclusions: - I. Z ≥ Q - II. I ≤ W - III. X > P 
- Statements: - P > Q < R; T ≤ U ≤ Q > S; V ≤ W < T - Conclusions: - I). P > V - II). T = S - III). R > V ...
- Statement: N < M; G ≤ V = M; J > V; K ≥ M - Conclusion: - I. J > K - II. K ≥ J 
- In the question, assuming the given statements to be true, find which of the conclusion (s) among given three conclusions is/are definitely true and th... 
- Statement: T > B = P `>=` C ; B `>=` J > F; O `<=` J `<=` C - Conclusions: I. J < T II. T > F ...
- Statements: F > G = J ≤ I = L > M ≥ K = N - Conclusion - I: N < I - II: L ≥ G 
- Statements: W > O > E ≤ N > P; L ≥ U; P > Q = R > U - Conclusions: - I. N > U - II. P > U - III. P < L - IV.... 
- In the question, assuming the given statements to be true, find which of the conclusion (s) among given two conclusions is /are definitely true and the... 
- Statements: R < S ≤ T = U; V ≤ W = R; P > U ≥ Q 
 Conclusions:
 I. V < T
 II. P > W
 III. Q < T
- In the following questions assuming the given statements to be true, find which of the conclusion among given conclusions is/are definitely true and th...