P5 Math: April and May

In April, Amy, Betty, Clara, and Dione had a total savins of $324.

In May, they each saved an equal amount when Amy saved twice as much, Betty saved $4 less, Clara saved the same, and Dione saved $9 more than in April. How much did Betty and Dione save altogether in April ?

Solution:

Quite tricky sentences.

Two equations

(1) In April, A + B + C + D = 324

(2) In May, u + u + u + u

while

A = 1/2u
B = u + 4
C = u
D = u - 9

Solve (1) by substituting letters to values, 3.5u = 329, u = 94.

Now (B + D) = 2u - 5= 188 - 5 = 183

There is second method using model, that is not involving negative operation

From first picture, the facts are:

(i) B + D = 4u + 4 - 9

(ii) 7u = 324 - 4 + 9 = 320 + 9 = 329

        u = 329 / 7 = 47

Solve (i)

B + D = (4 * 47) + 4 - 9 = 188 + 4 - 9 = 183