NCERT Exemplar Solutions
Class 7 - Mathematics - Unit 7: Comparing Quantities - Problems and SolutionsQuestion 117
Class 7 - Mathematics - Unit 7: Comparing Quantities - Problems and Solutions
Question. 117
(a) Science Application: The king cobra can reach a length of 558 cm. This is only about 60% of the length of the largest reticulated python. Find the length of the largest reticulated python.
(b) Physical Science Application: Unequal masses... If mass1 = 24 kg at 3 m and length2 = 2 m, find mass of child on right.
(c) Life Science Application: A DNA model was built using the scale 2 cm : 0.0000001 mm. If the model of the DNA chain is 17 cm long, what is the length of the actual chain?
Answer:
(a) 9300 cm
(b) 36 kg
(c) 0.000000085 mm
Detailed Answer with Explanation:
(a) Python length = 558 ÷ 0.6 = 930 cm = 9300 cm.
(b) Mass2 = (mass1 × length1) ÷ length2 = 24 × 3 / 2 = 36 kg.
(c) Scale 2 cm = 0.0000001 mm ⇒ 17 cm = 0.000000085 mm.