# ratio/proportions

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a geologist found that silt was deposited on a river bed at the rate of 4cm every 170 years , how long would it take for 5 cm of silt how long would it to be deposited ???? plz helpp

• ratio/proportions -

4/170 = 5/x

Cross multiply and solve for x.

• ratio/proportions -

I got 850/x and 4 /x what do I do next to get the answer

• ratio/proportions -

When we cross multiply, we multiply the first and last terms together. Then we multiply the two middle terms together.

4/170 = 5/x

4x = 850

Divide both sides by 4

x = 212.5 years

It'll take 212.5 years for 5 cm of silt to be deposited.

• ratio/proportions -

thx u

• ratio/proportions -

You're welcome.

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