A pet shop has a total of 21 dogs and birds. Altogether there are 56 feet. How many dogs are there and how many birds? A. 6 dogs and 15 birds B. 7 dogs and 14 birds C. 9 dogs and 12 birds D. 8 dogs and 13 birds

Let \( d \) be the number of dogs and \( b \) be the number of birds. We are given: 1. Total animals: \[ d + b = 21 \] 2. Total feet (dogs have \( 4 \) feet and birds have \( 2 \) feet): \[ 4d + 2b = 56 \] **Step 1: Express \( b \) in terms of \( d \) from the first equation.** \[ b = 21 - d \] **Step 2: Substitute \( b = 21 - d \) into the second equation.** \[ 4d + 2(21 - d) = 56 \] **Step 3: Simplify and solve for \( d \).** \[ 4d + 42 - 2d = 56 \] \[ 2d + 42 = 56 \] \[ 2d = 56 - 42 \] \[ 2d = 14 \] \[ d = 7 \] **Step 4: Find \( b \) using the value of \( d \).** \[ b = 21 - 7 = 14 \] Thus, there are \( 7 \) dogs and \( 14 \) birds. The correct answer is **B. 7 dogs and 14 birds**.