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3 years ago

Gerry's electric toothbrush rotates the brush 125 times per second.

Mathematics

1 answer:

makkiz [27]3 years ago

3 0

Answer:

Her electric toothbrush makes 210,000 rotations in one week

Step-by-step explanation:

Note that:

1 minute = 60 seconds

1 week= 7 days

∵ Gerry brushes her teeth for two minutes, twice a day

→ Twice means times 2

∴ Gerry brushes her teeth for 2 × 2 = 4 minutes a day

∵ Gerry's electric toothbrush rotates the brush 125 times per second

∵ 1 minute = 60 seconds

→ Multiply 125 by 60 to find the number of rotating in 1 minute

∴ Gerry's electric toothbrush rotates 125 × 60 = 7,500 in 1 minute

∵ Gerry brushes her teeth for 4 minutes a day

→ Multiply it by 4 to find the number of rotation in 1 day

∴ Gerry's electric toothbrush rotates 7,500 × 4 = 30,000 in 1 day

∵ 1 week = 7 days

→ Multiply the number of rotation in 1 day by 7 to find it in 1 week

∴ Gerry's electric toothbrush rotates 30,000 × 7 = 210,000 in 1 week

∴ Her electric toothbrush makes 210,000 rotations in one week

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