NCERT Exemplar Solutions
Class 7 - Mathematics - Unit 7: Comparing Quantities - Problems and Solutions
Question 117

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.

Open NCERT PDF