1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

# What will be the cost of painting a wall of area (m−4y) sq m. If cost of painting is $(3m−5y) per sq m. A$(3m217my+20y2)
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
B
$(3m2+17my+20y2) No worries! We‘ve got your back. Try BYJU‘S free classes today! C$(3m217my20y2)
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
$(3m2+17my20y2) No worries! We‘ve got your back. Try BYJU‘S free classes today! Open in App Solution ## The correct option is A$(3m2−17my+20y2)Given:––––––––– ∙ Area of the wall =(m−4y) sq m. ∙ Cost of painting =(3m−5y) per sq m. Need to Find:–––––––––––––––––– Cost of painting of the wall Cost of painting of the wall = Area of the wall × Cost of painting one sq. m =(m−4y)×$(3m−5y) Applying the FOIL rule, we get m×$3m=$3m(1+1)=$3m2 (∵am×an=am+n) The value of first term in the product (m−4y)×$(3m−5y) is$3m2. Now, we would multiply the "OUTER" terms in the product (m−4y)×$(3m−5y). (i.e., m and$(−5y)) m×$(−5y)=$(−5my) The value of second term in the product (m−4y)×$(3m−5y) is$(−5my). Now, we would multiply the "INNER" terms in the product (m−4y)×$(3m−5y). (i.e., −4y and$3m) −4y×$3m=$(−12my) The value of third term in the product (m−4y)×$(3m−5y) is$(−12my). Now, we would multiply the "LAST" terms in the product (m−4y)×$(3m−5y). (i.e., −4y and$(−5y)) −4y×$(−5y)=$20y(1+1)=$20y2 (∵am×an=am+n) The value of fourth term in the product (m−4y)×$(3m−5y) is $20y2. ∴ Cost of painting of the wall =(m−4y)×$(3m−5y) =$[3m2+(−5my)+(−12my)+20y2] =$[3m2+(−5my)+(−12my)––––––––––––––––––––––+20y2] Combining the like terms, we get =$(3m2−17my+20y2) The value of area of rectangle is$(3m2−17my+20y2). Therefore, option (a.) is the correct answer.

Suggest Corrections
1
Join BYJU'S Learning Program
Related Videos
Multiplication Using FOIL Rule
MATHEMATICS
Watch in App
Join BYJU'S Learning Program