Henry solve a certain number of algebra problems in an hour, but his older brother frank solved 3 times as many, together they solve 60.
how many was solved be each?

Rachel is studying the population of a particular bird species in a national park. she observes every 10th bird of that species that she can find in the park. her conclusion is that the birds living in the park who belong to that species generally feed on insects. rachel's sample is . based on the sample she picked, rachel's generalization is . reset next