Jo's lunch contains the most calories because if its twice breakfast and breakfast is 450 multiply that X2 you get 950. Then add 950 plus 450 you get 1400 then subtract 1400 from 2200 then you get the remaining 800 calories which shows that the most calories she eats is in her lunch meal.
To find the area, multiply length by width (lw, or l×w). If the length is 10, that just leaves the width, which is unknown. We can substitute 10 for l, which leaves us with 10w.
