when a watch is sold at ksh.126 a loss of x% is made if sold at ksh.154 aprofit of x%is realized .find the buying price

ksh 140.

Step-by-step explanation:

when a watch is sold at ksh.126 a loss of x%. This can be summarised as follow:

Selling price (Sp) = ksh 126

Percentage loss = x%

Cost price (Cp) =?

Percentage loss = Cp – Sp/Cp x 100

x% = Cp – 126/Cp (1)

if sold at ksh.154 a profit of x% is realized. This can be summarised as follow:

Selling price (Sp) = ksh 154

Percentage gain = x%

Cost price (Cp) =?

Percentage gain = Sp – Cp/Cp x 100

x% = 154 – Cp/Cp (2)

Equating equation 1 and 2, we have:

x% = Cp – 126/Cp (1)

x% = 154 – Cp/Cp (2)

Cp – 126/Cp = 154 – Cp/Cp

Cross multiply

Cp(Cp – 126) = Cp(154 – Cp)

Cancel out Cp

Cp – 126 = 154 – Cp

Collect like terms

Cp + Cp = 154 + 126

2Cp = 280

Divide both side by 2

Cp = 280/2

Cp = 140

Therefore, the cost price otherwise known as the buying price is ksh 140.

a) justify

step-by-step explanation:

justifying is just part of everyday life. justify kind of means proof so i think the answer is a) justify.