How Old Is John?
Joe is 4 years older than John. Sam is twice as old as Joe. The sum of their age is 68.
1 Answer - Sort by: Date | Rating
Write out the equations as you read them;
Joe = John + 4
Sam = 2 x Joe
Joe + John + Sam = 68
You have 3 equations and 3 unknowns. If they are independent equations, you can find a solution.
Substitute
2 x (John + 4) for Sam
and John + 4 for Joe
(John + 4) + (John) + 2(John + 4) = 68
Now you have one equation and one unknown. Solve for John;
John + 4 + John + 2John + 8 = 68
4John = 56
John = 56/4 = 14
Now we can calculate the rest;
Joe = John + 4 = 14 + 4 = 18
Sam = 2(Joe) = 2(18) = 36
Now, don't assume it's correct until we check everything;
Joe + John + Sam = 18 + 14 + 36 = 68
yes, it checks, so there you go.
Joe = John + 4
Sam = 2 x Joe
Joe + John + Sam = 68
You have 3 equations and 3 unknowns. If they are independent equations, you can find a solution.
Substitute
2 x (John + 4) for Sam
and John + 4 for Joe
(John + 4) + (John) + 2(John + 4) = 68
Now you have one equation and one unknown. Solve for John;
John + 4 + John + 2John + 8 = 68
4John = 56
John = 56/4 = 14
Now we can calculate the rest;
Joe = John + 4 = 14 + 4 = 18
Sam = 2(Joe) = 2(18) = 36
Now, don't assume it's correct until we check everything;
Joe + John + Sam = 18 + 14 + 36 = 68
yes, it checks, so there you go.
1
0
Thank you for your answer. Although it is lengthier than I had thought. Is there any other way to answer this problem?
Nice explanation my friend! I'll give ya a wow!...♥nassy
I just wanted you to see the steps. Yes, there are shorter ways to solve simultaneous equations, but leave that for college.
- How To Write Equation In Slope Intercept Form?
- When Does Root Act Breathing Tube?
- When Does Root Store Food?
- How Long Does It Take To Get From Hammersmith To Kings Cross On The Underground?
- What Is Spencers Real Name?
- What Is The Discriminant Of 12x^2=12x-3?
- What Number Does 3 4 And 5 Go Into?
- How Do You Complete Sr[?
- I Received A Sum Of Money And Know It Is 60% Of The Total Amount. How Do Calculate The Total Amount?
- What's Greater 1/5 Or 3/16?
- How Many Number 1's Have Take That Had?
- How To Write Fractions From Least To Greatest?
- How Can I Find Who The Number 81404 Is?
- How Do I Solve This Equation For X: 4x - 2y = 6?
- Which Ordered Pair Below Has An X-coordinate Value Of 2, And A Y-coordinate Value Of –1?
- How Many Hours By Train From Atlanta To Maryland?
- How Do You Solve 2l+2w For W?
- How Many Mg's Is In 50,000 IU Of Vitamin D 3?
- What Are The Missing Numbers In This Sequence 44-4245-43?
- How Does An Increase In Human Population Change The Environment?
- How Many Kilograms Do Teenagers Supposed 2 Way?
- What Is An Immediate Goal?
- What Is The Symbol For A Train Station?
- A Relation R (a, B, C, D, E, F) Have The Following Set Of Dependency: A-cd; B-c; F-de;f-a Is The Decomposition Of R In R1 (a, B, C,), R2 (a, F, D) And R3 (e, F) Dependency Reversing?
- How Much Do Hairstylists Get A Year?
New Comment - Comments are editable for 5 min.