A lumberman stacks planks of wood, starting with 30 planks in a row. Each row he stacks has one less plank than the row below it. The last row he stacks has 15 planks. How many rows of planks has he stacked?

12

15

16

18

These ARE Fractions BTW Which unit rate is equivalent to 19 miles per gallon? three gallons over fifty seven miles fifty seven miles over three gallons thirty seven miles over four gallons four gallons over thirty seven miles

The cost of dinner for Mr. and Mrs. Manning was $34.00, but with the tip, they spent $39.10. What percent tip did they give, rounded to the nearest integer?

Find the sale price to the nearest cent of a pair of jeans that originally cost $40 and are 15% off

The products of half my number times my number is 162. What is twice my number

Mitzi has 38 coins. She divides the coins equally among herself and her 3 brothers. How many coins does each person get? Are any coins left over?

Seven people are seated in a row. they all get up and sit down again in random order. what is the probability that the two people originally seated at the two ends are no longer at the ends after they sit down again

Five-X=12 what does x=?

Joseph had 380 heartbeats in 4 minutes how many heartbeats did he have in 15 minutes

What is the answer for m+12=10

Kerion can make 12 necklaces in 2 hours how long will it take for her to make 10 necklaces