Twice jack's age plus 5 is 21. write and solve an equation. how old is jack? a) 8 b) 13 c) 32 d) 52

Jack is 8 years old (option A)

Step-by-step explanation:

Hi, to answer this question we have to write an equation using the information given:

Twice : Means that the age of jack (j) is multiplied by 2 (2j),  

Plus 5: we have to add 5 (2j+5).  

Is 21: all is equal to 21.

Mathematically speaking:

2j +5 =21

Solving:

2j =21-5

2j =16

j= 16/2

j=8

Option A). 8

Feel free to ask for more if needed or if you did not understand something.

let soccer = x and golf = y

part a

1st equation: x + y = 125

2nd equation: x = y +45

part b

replace x in the 1st equation with the 2nd one:

y + 45 + y = 125

simplify:

2y + 45 = 125

subtract 45 from each side:

2y = 80

divide both sides by 2:

y = 80/2

y = 40

she plays golf for 40 minutes.

part c

no because she plays soccer for 45 minutes longer than golf 40 +45 =   85 minutes, not 80 minutes.

step-by-step explanation:

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