First find the total amount of paint Marla mixes by dividing the amount of blue paint by the percentage of the paint that's blue: 140 ounces / .7 = <<140/.7=200>>200 ounces
Then multiply the total amount of paint by the percentage that's white to find the number of white ounces: 200 ounces * 10% = <<200*10*.01=20>>20 ounces
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