Question

A village lost 15% of its cows in a flood and 10% of the remainder died of diseases. If the number of cows left now is 9180, what was the original number of cows before the flood?​

Answer 1

Answer: 12000

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Step-by-step explanation:

A loss of 15% means 85% remain (since 100-15 = 85)

The 85% converts to the decimal form 0.85

A loss of 10% means 90% remain, which gives the decimal form 0.90

Multiply those decimal values: 0.85*0.90 = 0.765

This tells us that after the two percentage losses, we have 76.5% of the cows remaining.

x = original number of cows

76.5% of x = 9180

0.765x = 9180

x = 9180/0.765

x = 12000

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Check:

• 15% of 12000 = 0.15*12000 = 1800 cows died in the flood
• 12000-1800 = 10200 cows remain (note how 85% of 12000 = 10200)
• 10% of 10200 = 0.10*10200 = 1020 more cows died from diseases
• 10200-1020 = 9180 cows remain (note how 90% of 10200 = 9180)

The answer is fully confirmed.