Example 3 In parts of New York City, the blocks between streets are called short blocks. There are 20 short blocks per mile. Blocks between avenues are called long blocks. There are 4 long blocks per mile. You walk 40 short blocks and 8 long blocks. How many miles do you walk? 4 mi 6 mi 12.5 mi 10.4 mi Multiple Choice Practice

Example 3 SOLUTION Read and Understand You walk 40 short blocks and 8 long blocks. There are 20 short blocks per mile and 4 long blocks per mile. You are asked to find how many miles you walk. Make a Plan Convert short blocks to miles and long blocks to miles using unit analysis. Then add to find the total miles. Multiple Choice Practice

Example 3 Solve the Problem Because 20 short blocks equal one mile, you can multiply the number of short blocks by to convert to miles. 20 short blocks 1 mile You can convert long blocks to miles by multiplying by. 4 short blocks 1 mile Multiple Choice Practice 40 short blocks  1 mile 20 short blocks = 2 miles = miles 8 long blocks  1 mile 4 long blocks = 2 miles = 4 8 miles

Example 3 You walk a total of miles miles. 4 = ANSWER The correct answer is A. Look Back Check your answer by drawing a diagram. From the diagram you can see that 40 short blocks are 2 miles and 8 long blocks are 2 miles, which is a total of 4 miles. So, your answer checks. Multiple Choice Practice

Guided Practice 2. for Example 3 WHAT IF? In Example 3, how many miles do you walk if you walk 60 short blocks and 16 long blocks? ANSWER 7 mi