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Phillip can do 15 math problems in 5 minutes. How long will it take him to do 21 math problems?

Respuesta :

yyan

One math problem:5min divide 15=0.3 min

21 math problem:21 x 0.3min=6.3 min

Answer:

7 minutes

Step-by-step explanation:

  1. Set up a proportion: [tex]\frac{5}{15} = \frac{x}{21}[/tex]  
  2. Cross multiply, then divide: 5 × 21 = 105, 105 ÷ 15 = 7
  3. So, it takes Phillip 7 minutes to do 21 math problems

I hope this helps!