lemon cakes

[leonswati]

A cake bakery sells white cakes, lemon cakes, and combination cakes that have one white layer and one lemon layer. Combination cakes currently comprise 20% of the bakery's inventory. The number of white cakes plus the number of combination cakes totals 98. If half of all the cakes are white cakes, how many of the cakes are lemon cakes?
12
22
30
42
48

The correct answer is D. I got this question correct but I solved it using the answer choices, can someone use the formula and get this answer...

[knight247]

Let the number of cakes be x
Let number of Lemon, White and Combo cakes be L,W and C respectively.

C=20/100x=0.2x
W=x/2=0.5x

W+C=98

0.2x+0.5x=98
0.7x=98
x=98/0.7=140

W=140/2=70
C=20(140)/100=28
W+C=98
L=140-98=42 Hence E

[mehrasa]

A cake bakery sells white cakes, lemon cakes, and combination cakes that have one white layer and one lemon layer. Combination cakes currently comprise 20% of the bakery's inventory. The number of white cakes plus the number of combination cakes totals 98. If half of all the cakes are white cakes, how many of the cakes are lemon cakes?
12
22
30
42
48

The correct answer is D. I got this question correct but I solved it using the answer choices, can someone use the formula and get this answer...

T= total inventory
white= 0.5 total combination= 0.2 total
0.5 T+ 0.2 T = 98
0.7 T = 98
T = 140
lemon cake= 1 - 0.7= 0.3 total
0.3 *140 = 42