Yesterday, nina's lunch cost $9.80 and she left a $1.47 tip. today, nina's lunch cost $12.60. if she tips the same rate that she did yesterday, how much tip should nina leave?

Olga used 100 ounces of flour to make 225 muffins. how many ounces of flour will be used to make 300 muffins?

Determine the difference: 3.2 × 1010 – 1.1 × 1010. write your answer in scientific notation.

Ariana starts with 100 milligrams of a radioactive substance. the amount of the substance decreases by 20% each week for a number of weeks, w. the expression 100(1−0.2)w finds the amount of radioactive substance remaining after w weeks. which statement about this expression is true? a) it is the difference between the initial amount and the percent decrease. b) it is the difference between the initial amount and the decay factor after w weeks. c) it is the initial amount raised to the decay factor after w weeks. d) it is the product of the initial amount and the decay factor after w weeks.