Solve exponential equations using logarithms

Question 1

Daniel invests $8000 at 5% compound interest per year. After how many whole years will the investment first be worth at least 2 times as much?

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Question 2

Solve 3^x = 196. Give x to 3 decimal places.

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Question 3

Solve 3 × 1.5^x = 87. Give x to 3 decimal places.

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Question 4

Sam invests $12000 at 4% compound interest per year. After how many whole years will the investment first be worth at least 1.5 times as much?

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Question 5

Solve 2^x = 193. Give x to 3 decimal places.

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Question 6

Solve 8 × 1.2^x = 152. Give x to 3 decimal places.

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Question 7

Hana invests $10000 at 4% compound interest per year. After how many whole years will the investment first be worth at least 1.5 times as much?

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Question 8

Solve 3^x = 158. Give x to 3 decimal places.

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Question 9

Solve 9 × 3^x = 72. Give x to 3 decimal places.

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Question 10

Maya invests $13000 at 6% compound interest per year. After how many whole years will the investment first be worth at least 2 times as much?

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Question 11

Solve 2^x = 67. Give x to 3 decimal places.

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Question 12

Solve 6 × 1.5^x = 192. Give x to 3 decimal places.

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Question 13

Kofi invests $2000 at 5% compound interest per year. After how many whole years will the investment first be worth at least 3 times as much?

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Question 14

Solve 2^x = 25. Give x to 3 decimal places.

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Question 15

Solve 5 × 2^x = 175. Give x to 3 decimal places.

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Question 16

Mateo invests $9000 at 5% compound interest per year. After how many whole years will the investment first be worth at least 2 times as much?

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