Mr. Bower has 3 times as many pens as pencils. He has 20 pens and pencils altogether. How many pens does he have?
Solve by trial and error:
Say you have 1 pencil, then you have 3 pens ( 3 times 1 = 3)
1 + 3 = 4, so you don't get 20
Say you have 3 pencils, then you have 9 pens ( 3 times 3 = 9 )
3 + 9 = 12, so you don't get 20
Say you have 4 pencils, then you have 12 pens ( 3 times 4 = 12 )
4 + 12 = 16, so you don't get 20
Say you have 5 pencils, then you have 15 pens ( 3 times 5 = 15)
Since 5 + 15 = 20, then you have 5 pencils and 15 pens.
May 21, 17 09:19 PM
Sharpen your math skills by grade here with crystal clear lessons
New math lessons
Your email is safe with us. We will only use it to inform you about new math lessons.
May 21, 17 09:19 PM
Sharpen your math skills by grade here with crystal clear lessons