After an oil spill, the ratio of contaminated water samples to clean water samples in the ocean is 7:2. Jai found 140 clean samples.
How many fewer samples were clean than were contaminated?

Answer this question! 30 points and brainliest!

Marla bought a book for $12.95, a binder for $3.49, and a backpack for $44.99. the sales tax rate is 6%. find the amount of tax and the total she paid for these items

Prove the divisibility of the following numbers: 25^9 + 5^7 is divisible by 30.also, read as (25 to the power of 9) + (5 to the power of 7) is divisible by 30. blank x 30what is the blank? ( it should be expressed in exponent form)