Given:
5 letters were completed in Mr. Larsen's class.
12 letters were completed in Ms. Ortega's class.
Mr. Larsen plans to teach his class 2 new letters per week, and Ms. Ortega intends to cover 1 new letter per week.
Mr. LarsenLet x be the number of letters learned in Mr. Larsen's class.
Let y be the number of letters learned in Ms. Ortega's class.
Let t be the number of weeks.
[tex]x=5+2t[/tex][tex]y=12+(1)t[/tex]
The same number of letters learned after t weeks. So x=y.
Set x=y, to find the value for t.
[tex]5+2t=12+t[/tex]Subtracting t from both sides, we get
[tex]5+2t-t=12+t-t[/tex][tex]5+t=12[/tex]Subtracting 5 from both sides, we get
[tex]5+t-5=12-5[/tex][tex]t=7\text{ w}eeks[/tex]After 7 weeks the students in both classes will know how to write the same number of letters
Substitute t=7 in x to find the number of letters.
[tex]x=5+2\times7[/tex][tex]x=5+14[/tex][tex]x=19\text{ letters}[/tex]The students know 19 letters.
Hence after 7 weeks, the students in both classes will know how to write 19 letters.