Multiple choice

The weight of a body as calculated by the average of 7 different experiments is 53.735 kg. The average of the first three experiments is 54.005 kg. and the fourth is 0.004 kg greater than the fifth, while the average of the sixth and seventh experiment was 0.010 kg. less than the average of the first three. Find the weight of the body obtained by the fourth experiment. 7 विभिन्न प्रयोग से शरीर के औसत वजन की गणना 53.735 किग्रा. की गयी। पहले तीन प्रयोगों का औसत 54.005 किग्रा. है और चौथा, पांचवे से 0.004 किग्रा. अधिक है । छठे और सातवें प्रयोग का औसत पहले तीन प्रयोगों के औसत से 0.010 किग्रा. कम था। चौथे प्रयोग से प्राप्त वजन क्या था?

  1. 51.472 kg.

  2. 52.152 kg.

  3. 52.882 kg.

  4. 53.072 kg.

  5. 54.702 kg.

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Total of 7 experiments: 53.735×7=376.145. First 3 experiments: 54.005×3=162.015. Let 6th and 7th average = 54.005-0.010=53.995, so their sum=107.99. Let 5th experiment = x, then 4th = x+0.004. Sum equation: 162.015 + (x+0.004) + x + 107.99 = 376.145. Solving: 2x + 270.009 = 376.145, so 2x=106.136, giving x=53.068. Fourth experiment: 53.068+0.004=53.072. ✓