Kent has 20 pieces of 50 sen and 20 sen coins. The total value of the coins is RM6.10. How many 50 sen coins does he have?

Number of 50sen coins  =  13

Step-by-step explanation:

Let the number of 50sen coins be = x

Let the number of 20sen coins be  = y

Total coins  = 20

x + y = 20 (i)

Value of 50sen coins = 0.50*x = 0.50x

Value of 20sen coins = 0.20 *y = 0.20y

Total value = RM 6.10

0.5x + 0.2y = 6.10 (ii)

Multiply (i) by (-0.5) and then add the equations. So, x will be eliminated and we can find the value of y

(i) * (-0.5)      -0.5x - 0.5y = -10

(ii)                  0.5x  + 0.2y = 6.10 { add and now x will be eliminated}

                              - 0.3y = -3.90

Divide both sides by (-0.3)

y = -3.90/-0.3

y = 13

Plug in the value of y in equation (i)

x + 13 = 20

Subtract 13 from both sides

x = 20 -13

x = 7

Number of 50sen coins  =  13

step-by-step explanation:

i am not sure sorry : c