NCERT Solutions Ganita Prakash (Part 1) Chapter 2 .1 Experiencing the Power Play … — In-text Questions

Book page 202 Updated on2026-09-05

Q1.

Now, what do you think the thickness would be after 30 folds? 45 folds? Make a guess.

Answer

After 30 folds, about 10.7 km. After 45 folds, about 3,51,844 km — very nearly the distance to the Moon (3,84,400 km).

30 folds: 0.001 cm × 2³⁰ = 10,73,741.8 cm = 10.737 km
45 folds: 0.001 cm × 2⁴⁵ = 3,51,84,37,20,888 cm ≈ 3,51,844 km

Use the table on this page to see how quickly the jumps grow. From fold 17 (131 cm) to fold 26 the thickness goes from about a person's height to 671 m — taller than most buildings in the country. Nine more folds after that and it is 343 km, higher than the space station.

Why it happens: the gap between one fold and the next is itself doubling. Fold 45 adds as much thickness as folds 1 to 44 put together, because 2⁴⁵ = 2⁴⁴ + 2⁴⁴. That is the signature of multiplicative growth: the last step is always as big as everything before it.

Q2.

Fill the table below. [Folds 18–26, 27–30 and 31–45]

Answer

Every entry is 0.001 cm × 2ⁿ, i.e. double the row above. Here are the values, converted to a sensible unit at each stage.

Fold	Thickness	Fold	Thickness	Fold	Thickness
18	≈ 262 cm	21	≈ 21.0 m	24	≈ 167.8 m
19	≈ 524 cm	22	≈ 41.9 m	25	≈ 335.5 m
20	≈ 10.4 m	23	≈ 83.9 m	26	≈ 671 m

Fold	Thickness	Fold	Thickness
27	≈ 1.3 km	29	≈ 5.4 km
28	≈ 2.7 km	30	≈ 10.7 km

Fold	Thickness	Fold	Thickness	Fold	Thickness
31	≈ 21.5 km	36	≈ 687 km	41	≈ 21,990 km
32	≈ 43.0 km	37	≈ 1,374 km	42	≈ 43,980 km
33	≈ 85.9 km	38	≈ 2,749 km	43	≈ 87,961 km
34	≈ 171.8 km	39	≈ 5,498 km	44	≈ 1,75,922 km
35	≈ 343.6 km	40	≈ 10,995 km	45	≈ 3,51,844 km

One more fold gives 46: ≈ 7,03,687 km — past the Moon.

Check it yourself: you never need a calculator for the next row. Just double. And you can jump ten rows at a time by multiplying by 1024, because 2¹⁰ = 1024.

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