1/5 of a class of children signed up for a mathematics competition. There were 10 boys and 30 girls who did not sign up. How man
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Answer:
15 seconds
Step-by-step explanation:
Because the split id 25% and 75%, we could create another average pretending that there are four kids, one who ran in 12 seconds, and three who ran in 16.
Equation for averages: (a₁ + a₂ + a₃ + ... )/ n
Plug in:<em> (12 + 16 + 16 + 16)/4</em>
Add: 60/4
Divide: 15 seconds