Question

The product of the length of 2 unequal poles before cutting 2 cm from each was 285 cm. Their present sum after cutting 2cm from each is 30cm. What is the length of the shorter pole? The product of the length of 2 unequal poles before cutting 2 cm from each was 285 cm . Their present sum after cutting 2cm from each is 30cm . What is the length of the shorter pole ?​

Answer 1

Answer:

15 cm

Step-by-step explanation:

The length of the shorter pole can be found by forming and subsequently solving 2 equations.

Start by defining the variables that are going to be used in the working.

Let the original length of the shorter pole be a cm and that of the longer pole be b cm.

'Product' refers to the multiplication operation.

ab= 285 -----(1)

On the other hand, 'sum' refers to the addition operation.

Length of shorter pole after cutting= a -2

Length of longer pole after cutting= b -2

(a -2) +(b-2)= 30

a +b -4= 30

Adding 4 to both sides:

a +b= 30 +4

a +b= 34 -----(2)

From (2):

a= 34 -b -----(3)

Let's solve by substitution:

Substitute (3) into (1):

b(34 -b)= 285

Expand:

34b -b²= 285

b² -34b +285= 0

Factorise:

(b -15)(b -19)= 0

b -15= 0       or       b -19= 0

b= 15            or             b= 19

Substitute into (1):

a(15)= 285       or       a(19)= 285

a= 285 ÷15      or             a= 285 ÷19

a= 19                or             a= 15

Since a <b, a= 15 and b= 19.

Thus, the length of the shorter pole is 15 cm.