How many combinations without repetition or possible if n equals 6 and R equals 3​

Part a : solve - vp + 40 < 65 for v . part b : solve 7w - 3r = 15 for r show your work!

Which expression is equivalent to the expression shown?

Dexter read 11 science fiction books and 5 history books. lena read 9 science fiction books and 4 history books. compare the students’ ratios of science fiction books to history books. 1. determine the ratios’ form:    science fiction books to history books 2. write the ratios as fractions:    dexter: 115; lena: 94 3. rewrite with a common denominator. 4. compare. 5. answer the question. determine which shows the correct comparison of the ratios for this problem.