+12 Edi bought some sweets. On Thursday, he gave some sweets to his friends. The number of sweets given on Thursday was 3/5 the number of sweets left. On Friday, he gave 130 sweets from the sweets left on Thursday to his neighbours. The total number of sweets given over the 2 days was 4 more than 9/16 of the number of sweets Edi had at first.
(a) How many sweets did Edi buy?
(b) How many sweets were left after the two days?
+129850 Call the original number of sweets = S
Call the sweets he gave to his friends on Thursday = T
(S - T) = sweets left after Thursday
Sweets given on Thursday = (3/5) of what was left
T = (3/5)(S-T) simplify
(8/5)T = (3/5)S
8T = 3S
T = (3/8)S (1)
Sweets given on Friday = 130
Sweets given over 2 days = 4 more the (9/16) of what he started with
T + 130 = (9/16)S + 4
T + 126 = (9/16)S (2)
Sub (1) into (2)
(3/8)S + 126 = (9/16)S
126 = (9/16 - 3/8)S
126 = (9/16 - 6/16)S
126 = (3/16)S
S = 126 * 16/3 = 672 = number of sweets Edi had at first
Sweets given after 2 days = 672 - [ (9/16)(672) + 4 ] = (7/16)(672) - 4 = 290
Sweets left after 2 days = 672 - 290 = 382
