If james is starting to save $150 to buy a new cell phone. In January he saved $5. In February he saved twice as much as he saved in January for a total of $15. If James continues to save twice as much each month as he saved the previous month, in which month will his totals savings be enough to buy the phone?

Need a step by step explanation please!

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.