1.
2 1/10 : 1 2/5 = 21/10 : 7/5 = 21/10 * 5/7 = 3/2 = 1 1/2,
4 1/2 : 5 1/4 = 9/2 : 21/4 = 9/2 * 4/21 = 6/7,
4 3/4 : 1/4 - 2 3/14 * 7 = 19/4 * 4/1 - 31/14 * 7/1 = 19 - 15 1/2 = 3 1/2,
2.
всего - 32 т,
1ц. - х,
2ц. - 7/9х
х + 7/9х = 32,
1 7/9х = 32,
х = 32 : 1 7/9,
х = 32 : 16/9,
х = 32 * 9/16,
х = 18 т - в 1 цистерне,
7/9х = 7/9 * 18 = 14 т - во 2 цистерне,
3.
7/10 м - 1 2/5,
2 1/4 м - ?,
х = (2 1/4 * 1 2/5) / (7/10) = 9/4 * 7/5 * 10/7 = 9/2 = 4 1/2 (р.)
4.
4/9у + 1/3у = 6,3,
4/9у + 3/9у = 6,3,
7/9у = 6,3,
у = 6,3 : 7/9,
у = 63/10 * 9/7,
у = 8,1
5.
с/к + 4/5 = (5с + 4к) / 5к